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HX64098435 
QM455  .H85  An  Eskimo  brain.  By 


RECAP 


An  Eskimo  Brain 


BY 

ALES  HRDLICKA,  M.D. 

NEW   YORK 


THE  KNICKERBOCKER  PRESS 

NEW  YORK 

1901 


Q/W455 


MM 


Columbia  Stotoetsitp 

COLLEGE  OF 

PHYSICIANS  AND  SURGEONS 

LIBRARY 


Digitized  by  the  Internet  Archive 

in  2010  with  funding  from 
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http://www.archive.org/details/eskimobrainOOhrdl 


An  Eskimo  Brain 


BY 

ALES  HRDLICKA,  M.D. 

NEW    YORK 


THE  KNICKERBOCKER  PRESS 

NEW  YORK 

I9OI 


An  Eskimo  Brain 


BY 

ALES  HRDLICKA,  M.D. 

NEW   YORK 


THE  KNICKERBOCKER  PRESS 

NEW  YORK 

I9OI 


40  13778 


KISHU  AND  MENEE  (PHOTOGRAPHED  ON  THEIR  ADMISSION  TO  BELLEVUE   HOSPITAL) 


AN   ESKIMO   BRAIN 
By  ALES   HRDLICKA 

The  brain  in  question  '  is  that  of  Kishu  (or  Kissuk),  an  adult 
male  Eskimo  of  about  forty-five  years  of  age,  who  died  of  acute 
general  tuberculosis.2  Kishu  was  a  chief  of  his  tribe  ;  he  meas- 
ured 1.64  m.  in  height,  weighed  about  170  lbs.,  was  muscular, 
and  in  every  respect  normally  developed.  He  died  at  Bellevue 
Hospital  within  less  than  five  months  after  the  inception  of  his 
disease.  Plate  XIII  shows  him  (together  with  his  son)  as  he  ap- 
peared on  admission  to  the  hospital. 

The  autopsy  was  performed  in  my  presence  by  Dr  Harlow 
Brooks.  I  am  indebted  to  Dr  Brooks  for  notes  concerning  the 
general  condition  of  the  brain  and  its  membranes,  and  to  the 
authorities  of  Bellevue  hospital  and  the  American  Museum  of 
Natural  History  for  the  privilege  of  examining  the  specimen* 
Before  the  skull  was  opened,  I  obtained  the  following  measure- 
ments of  the  head : 

Diam.  antero-post.  max 19.8  cm. 

Diam.  lateral  max 1 5. 1  cm. 


1  The  specimen  was  examined  in  1896  and  reexamined  in  igoi.  A  preliminary 
report  on  it  was  published  by  the  author  in  the  Proceedings  of  the  Amer.  Medico- 
Psychological  Assoc,  1899,  and  a  full  report  in  the  American  Anthropologist, 
n.  s.,  3,  1901. 

8  Kishu  was  one  of  the  six  Eskimo  who  were  brought  to  New  York  in  1896  by 
Lieutenant  Peary,  from  the  neighborhood  of  Smith  sound.  Of  these  six  Eskimo, 
four,  including  Kishu,  have  since  succumbed  to  acute  tuberculosis  ;  one  was  sent  back 
to  Smith  sound,  and  a  boy  of  about  twelve  years  survives,  after  having  recovered  from 
incipient  pulmonary  tuberculosis,  in  the  care  of  Mr  Wallace,  the  former  Superintend- 
ent of  the  American  Museum  of  Natural  History.  The  brains  of  the  three  other 
Eskimo  who  died,  as  well  as  an  additional  specimen, — the  brain  of  an  Eskimo  girl 
from  Alaska, — will  be  reported  upon  in  detail  by  Mr  Edward  A.  Spitzka,  of  Columbia 
College.  Some  measurements  and  observations  which  I  have  made  of  these  brains 
will  be  included,  for  comparison,  in  this  paper. 

3 


4  AN  ESKIMO  BRAIN 

(Cephalic  index  76.26.) 
Height  (from  line  joining  the  aud.  meati  to 

bregma)  about I4-2  cm. 

Circumference  maximum  of  the  head 56.8  cm. 

Diam.  biauricular  (between  the  depressions 
over  the  roots  of  zygomae,  in  front  of 

the  ear) 13-2  cm. 

Diam.  frontal  minimum 10.4  cm. 

Diam.  bigonial 1 1 . 1  cm. 

Diam.  bizygomatic  max 14.5  cm. 

Height  of  face  :  chin  to  nasion 12.3  cm. 

chin  to  interciliary  line 14.3  cm. 

chin  to  insertion  of  hair 20.0  cm. 

These  measurements  agree  in  the  main  with  those  which  I 
made  of  the  other  Eskimo  from  the  same  locality,  thus  showing 
that  Kishu  was  not  racially  exceptional. 

The  scalp  was  found  to  be  less  than  the  average  in  thickness ; 
this  was  undoubtedly  due  to  advanced  general  emaciation.  The 
skull  was  entirely  symmetrical ;  the  sutures  mostly  still  pervious ; 
skull-cap  thin.  No  adhesion  of  the  dura ;  the  soft  membranes 
normal.  Several  masses  of  Pacchionian  granulations  over  the 
longitudinal  sinus.  No  signs  of  tuberculosis,1  nor  any  other 
pathological  lesion,  within  the  cranial  cavity.  Very  small  quan- 
tity of  fluid.  There  was  a  pronounced  pigmentation  of  the  pia 
and  arachnoid  from  the  pons  to  over  and  below  the  calamus 
scriptorius. 

Weight  of  brain,  denuded  of  dura  mater,  after  a  few  minutes' 
exposure  for  drain,  1503  grammes.2  The  specimen  was  laid  in 
20  parts  5  %  formaline  and  80  parts  95  %  alcohol. 


1  The  brain  and  the  heart  were  about  the  only  organs  in  which  no  tubercular  lesions 
were  found. 

2  Mean  weight  of  white  male  brain  in  154  men  of  mean  height  of  1.680  m.  equals 
1361.5  grams  (Broca) ;  mean  weight  of  white  male  brain  in  168  men  of  mean  height 
of  1.679  m-  equals  1357.5  grams  (Manouvrier). 


AN   ESKIMO   BRAIN  5 

Examination  of  the  Brain 

(Three  weeks  after  death) 

Weight 

The  brain  and  its  principal  parts,  denuded  of  the  membranes, 
weigh,  after  15  minutes'  drainage,  as  follows: 

Whole  encephalon 1 325.0  gr. 

(Loss  in  three  weeks  through  solution  and 

through  loss  of  membranes 178.0  gr.) 

Cerebrum 1 155.0  gr.  or  87.17%  of  the  total. 

Right  hemisphere 577.0  gr. 

Left  hemisphere 578.o  gr. 

Cerebellum 142.0  gr.  or  10.72  %  of  the  total. 

Pons  and  bulb 2S.0    gr.   or  2.1%  of  the  total. 

The  proportions  of  the  cerebrum  and  cerebellum  to  the  whole 
brain  are  very  nearly  like  those  of  whites,1  but  the  relative  weight 
of  the  pons  and  bulb  is  slightly  greater. 

GENERAL  OBSERVATIONS 

Cerebrum 

The  hemispheres  in  general  are  very  well  developed.  The 
gyration  is  pronounced  and  rather  more  complex  than  that 
found  on  the  brains  of  average  whites.  The  principal  sulci  are 
deep.  The  thickness  <>f  the  gray  matter  shows  no  appreciable 
difference  from  that  observed  in  the  brains  of  whites.  The  gyra- 
tion of  the  left  hemisphere  is  perceptibly  more  complex,  particu- 
larly in  the  frontal  lobes,  than  that  of  the  right.  A  striking 
feature  is  the  predominance  on  both  hemispheres,  but  more  espe- 
cially on  the  right,  of  vertical  gyration. 


1  In  the  white  brain,  the  proportionate  weight  of  the  cerebellum,  medulla,  and 
pons  together  is  to  that  of  the  whole  brain  in  the  adult  as  13  to  87  (Huschke).  The 
cerebellum  is  10.7  of  the  lotal  encephalon  (Meynert).  According  to  Broca,  the  rela- 
tive weights  to  that  of  the  whole  encephalon  are:  cerebrum,  87.3$  ;  cerebellum,  ro.6  %; 
pons  and  bulb,  1.91  %.  As  to  the  hemisphere,  in  264  men  Broca  found  the  right  to 
be  the  heavier  in  138  cases,  the  left  in  105  cases  ;  the  weight  was  even  in  21  cases. 


6  AN  ESKIMO  BRAIN 

The  hemispheres  show  certain  gross  and  many  small  asym- 
metries. The  principal  of  the  gross  asymmetries  are  the  differ- 
ences in  the  limbic,  temporo-sphenoidal,  and  occipital  lobes.  All 
these,  as  well  as  the  minor  peculiarities  of  the  brain,  will  be 
described  later. 

Norma  Superior. — Viewed  from  above,  the  cerebrum  is  dis- 
tinctly hexagonal  in  its  outline.  The  longest  sides  of  the  hexagon 
are  the  antero-lateral  lines,  upon  which  follow,  in  the  order 
named,  the  anterior,  the  postero-lateral,  and  the  posterior  lines. 
The  outline  of  the  frontal  lobes  is  quite  angular. 

The  Norma  Lateralis,  or  the  outline  of  the  cerebrum  when 
looked  at  from  the  side,  is  obliquely  quadrilateral.  The  antero- 
inferior line  (base  of  the  frontal  with  the  antero-inferior  boundary 
of  the  temporal  lobes),  and  the  postero-inferior  boundary  (base 
of  temporal  and  occipital  lobes),  are  nearly  straight.  The  two 
superior  lines,  moderately  convex,  meet  over  the  precuneus. 

The  right  temporal  lobe  is  perceptibly  higher  than  the  left. 

There  are  a  few  specially  prominent  points  on  the  external 
surface  of  each  hemisphere :  on  the  left  such  points  are  the 
supramarginal  and  the  second  temporal  gyri ;  on  the  right,  the 
supramarginal  (somewhat  less  than  on  left),  second  temporal,  and 
ascending  parietal  convolutions. 

Norma  Ventralis,  or  the  outline  of  the  base  of  the  hemi- 
spheres, is  oval,  almost  square  anteriorly  and  tapering  posteriorly. 
The  basal  surface  of  the  frontal  lobes  slopes  toward  the  middle 
and  there  is  a  marked  elevation  on  each  frontal  lobe  along  the 
median  fissure.  These  elevations  are  somewhat  larger  than  those 
found  ordinarily  in  the  brains  of  whites.  The  olfactory  nerves 
run  along  their  middle.  Each  of  the  elevations  comprises  ap- 
proximately two-sevenths  of  the  base  of  each  frontal  lobe,  and 
they,  together  with  the  sloping  of  the  rest  of  the  basal  surfaces, 
impart  to  the  inferior  portion  of  the  approximated  frontal  lobes  a 
boat-keel-like  appearance. 

Norma  Anterior.— The   outline  of  the  anterior  lobes  forms 


AN  ESKIMO   BRAIN  J 

superiorly  and  laterally  a  regular  arch,  while  inferiorly  it  consists 
of  two  shallow  arches  (concavities  of  the  inferior  surface  of  the 
frontal  lobes),  which  meet  over  the  median  eminence.  The 
outer  terminal  points  of  the  arches  are,  as  usual,  situated  higher 
than  the  inner  ones. 

The  anterior  surface  of  the  frontal  lobes  is  almost  vertical. 

Principal  Measurements  of  the  Cerebrum  ' 

Length  maximum  of  left  hemisphere 18.0  cm. 

Length  maximum  of  right  hemisphere 17.9  cm. 

Width  maximum  of  cerebrum 13.6  cm.3 

As  to  the  parts  situated  at  the  base  of  the  cerebrum,  nothing 
unusual  was  found.  The  anterior  perforated  spaces  are  not 
appreciably  larger  than  in  whites.  The  optic  commissure  is  well 
formed  ;  the  optic  nerves  are  strong.  Hypophysis  of  ordinary 
size  and  appearance.  Crura  cerebri,  cut  at  the  niveau  of  the 
mesial  border  of  the  hippocampal  gyri,  are  exactly  equal  in  size. 
Their  cross-section  measures  on  each  side  2.8  cm.  in  greatest 
length  and  1.7  cm.  in  greatest  width. 

There  were  no  marked  anomalies  in  the  cerebral  circulation. 
The  ventricles  were  not  opened. 

External  Conformation  of  the  Hemispheres 
principal  sinuosities.  fissure  of  sylvius 
The  horizontal  and  ascending,  or,  more  properly  in  this  case, 
the  anterior  and  posterior,  branches  of  the  pre 'sylvian  begin  sepa- 
rately, from  the  superior  limiting  sulcus  of  the  insula  on  the 
right,  and  from  a  common  fovea,  connecting  with  that  sulcus,  on 
the  left  side.3  The  anterior  branch  is  in  line  with,  and  appears 
like  a  continuation  of,  the  anterior  limiting  sulcus  of  the  insula. 

1  For  additional  and  comparative  measurements,  see  the  end  of  the  paper. 

*  By  an  oversight  this  measure  was  given  in  the  preliminary  report  as  14.2  cm., 
which  was  incorrect. 

3  This,  according  to  Cunningham,  is  also  frequently  the  case  in  whites.  In 
80  hemispheres  examined  by  that  author,  two  separate  limbs  of  the  presylvian  were 
found  15  times  (32.6  %)  on  the  right  and  15  times  (44.1  %)  on  the  left  side. 


8  AN  ESKIMO  BRAIN 

Length  of  the  anterior  branch,  1.,  2.8  cm.,  r.,  2.6  cm. 
Length  of  the  posterior  branch,  1.,  1.2  cm.,  r.,  2.0  cm. 

On  the  left  the  posterior  branch  is  very  short,  and  on  both 
sides  the  anterior  branch  is  the  longer  (the  reverse  of  that  gen- 
erally found  in  white  people). 

The  anterior  branch  connects  on  the  right,  over  a  submerged 
but  not  deep  gyrus,  with  a  descending  branch  from  the  inferior 
frontal  sulcus. 

The  several  important  opercula  situated  along  the  lower 
border  of  the  hemispheres  in  the  neighborhood  of  these  two  an- 
terior branches  of  the  Sylvian,  differ  somewhat  in  size  and  form. 
(See  the  description  of  the  inferior  frontal  gyrus.) 

The  stem  or  main  limb  of  the  Sylvian  runs  in  a  nearly 
straight  line ;  it  measures,  from  the  anterior  branch  of  the  pre- 
sylvian  to  the  bifurcation,  6.5  cm.  on  the  left  and  5.2  cm.  on  the 
right  hemisphere.1 

The  depth  of  the  Sylvian  fissure  is  considerable  throughout. 
It  measures  : 

Left  Right 

At  the  origin  (x)  of  the  anterior  branches 3.0  cm.         3.1  cm. 

In  middle  between  x  and  the  precentral  sulcus.. .  .    2.9  cm.         2.6  cm. 
Opposite  the  precentral  sulcus 2.8  cm.         2.7  cm. 

The  anterior  branch  of  the  presylvian  measures  at  middle, 
left,  2.4  cm.  ;  right,  2.2  cm.  Of  the  terminal  branches  of  the 
Sylvian,  the  superior  measures,  left,  2.6  cm.  ;  right,  2.2  cm.  The 
inferior  measures,  left,  1.8  cm.  ;  right,  about  0.8  cm.  in  depth. 

The  above  figures  show  that,  except  at  its  beginning,  the  left 
Sylvian  is  the  deeper  at  all  points  of  measurement. 

The  main  limb  of  the  Sylvian  presents  the  following  points  of 
interest  on  the  two  sides  of  the  brain  : 

On  the  left,  0.5  cm.  behind  the  posterior  presylvian,  there  be- 
gins within  the  Sylvian,  over  a  deep  annectent  loop,  by  means 

1  The  left  fissure  is  longer  than  the  right  one  in  the  whites*  and  the  disproportion 
"is  evident  at  all  points  of  growth"  (Cunningham,  Contr.  to  the  Surf.  Anat.  of  the 
Cerebr.  Hemispheres,  1892,  p.  127  ;  also  Eberstaller). 


AN  ESKIMO  BRAIN  9 

of  the  diagonal  sulcus,  a  pronounced,  long,  composite,  vertical 
furrow,  which  runs  nearly  parallel  with  the  central  fissure  and  the 
precentral  sulci,  and  terminates  above  not  far  from  the  superior 
border  of  the  hemisphere.  The  sulcus  shows  a  number  of  medium 
deep  and  deep  annectent  fascicles. 

On  the  right  a  similar  furrow  begins  from  the  Sylvian,  over  a 
submerged  loop,  0.6  cm.  posteriorly  to  the  hinder  branch  of  the 
presylvian,  and  ascends  in  a  quite  straight  line  to  within  a  few 
millimeters  of  the  superior  frontal  sulcus.  This  furrow,  in  aver- 
age as  well  as  at  maximum,  is  deeper  than  that  on  the  left 
(maximum  depth  on  the  right,  1.7  cm.). 

A  little  over  1.0  cm.  posteriorly  to  the  last  mentioned  furrow 
there  begin  from  the  Sylvian,  on  both  sides,  over  a  loop  situated 
very  deeply  on  the  right  and  at  medium  depth  on  the  left,  the 
central  fissures. 

The  base  of  the  ascending  frontal  gyrus  shows  on  each  side  a 
small  trans-precentral,  the  base  of  the  ascending  parietal  convolu- 
tion a  similar  trans-postcentral  sulcus.  These  sulci  on  the  right  side 
are  entirely  hidden  in  the  Sylvian,  but  on  the  left  side  both  reach 
to  and  slightly  beyond  the  inferior  border  of  the  convolutions. 

Finally,  0.5  cm.  anterior  to  the  bifurcation  on  the  right  and 
almost  at  it  on  the  left,  the  Sylvian  connects  on  each  side,  over  a 
submerged  but  quite  superficial  gyrus,  with  the  united  postcentral 
sulcus. 

The  inferior  lip  of  the  Sylvian  shows  on  the  left  the  extremi- 
ties of  four,  on  the  right  of  three,  transtemporal  depressions.  One 
of  these  furrows  on  the  left  and  one  on  the  right  effect  a  shal- 
low communication  with  the  superior  temporal  sulcus. 

Of  the  terminal  branches  of  the  Sylvian  the  superior  is  2.4  cm. 
in  length  on  the  left,  and  2.6  cm.  on  the  right  side  ;  they  both 
end,  as  usual,  in  the  supramarginal  gyrus.  The  inferior  ramus  on 
the  left  runs  3.0  cm.  horizontally  and  bifurcates ;  one  of  its 
branches,  2.5  cm.  long,  passes  upward  into  the  angular  gyrus, 
while  the  other,  1.0  cm.  long,  descends  backward.     On  the  right 


10  AN  ESKIMO  BRAIN 

the  inferior  terminal  branch  runs  1.5  cm.  backward  and  down- 
ward and  joins,  over  a  deep  gyrus,  the  first  temporal  sulcus. 

The  superior  terminal  branch  on  the  left  makes  two  connec- 
tions :  one,  shallow,  posteriorly,  with  a  sulcus  running  downward 
and  forward  from  the  interparietal,  and  one,  deeper,  anteriorly, 
with  a  horizontal  furrow  running  backward  from  the  lower  part 
of  the  postcentral  sulcus.  The  inferior  branch  on  the  left  con- 
nects, not  far  from  the  bifurcation,  over  a  submerged  annectent 
gyrus,  with  the  posterior  portion  of  the  first  temporal  sulcus. 

On  the  right  side  the  superior  terminal  branch  of  the  Sylvian 
fissure  is  better  developed  than  the  inferior,  and  is  deeper  than 
the  latter.  It  ascends  for  2.0  cm.  into  the  supramarginal  gyrus, 
running  parallel  to  the  central  fissure,  and  ends  in  a  short  T. 
The  lower  terminal  branch  descends  for  1.3  cm.,  over  two  medium 
deep  anastomotic  fascicles,  and  joins  the  ascending  ramus  of  the 
first  temporal  sulcus. 

Annectent  Gyri. — On  the  left  a  strong  column,  at  medium 
depth,  between  parietal  and  temporal  lobes,  at  the  beginning  of 
the  lower  terminal  branch  of  the  Sylvian.  On  the  right  a  similar 
but  more  superficial  column,  at  the  beginning  of  the  inferior 
branch,  and  another  more  posteriorly  in  the  same. 

CENTRAL    FISSURE 

Left  Right 

Length  (in  a  straight  line,  with 

sliding  compass) 9.0  cm.  (50  $  of  the  total     8.6  cm.  (48  <f0).1 

length    of   the 
hemisphere) 
Depth,  maximum 2.3  cm.  2.5  cm. 

The  fissure  begins  on  both  sides  within  the  Sylvian,  probably 
by    means  of  the  subcentral   sulci   of  Eberstaller.2     The  origin 

1  According  to  Schafer  (Quain's  Anat.,  10th  ed.,  ill,  1,  p.  143),  "the  length  of 
the  fissure  in  whites  is  about  2/5  (or  40  %)  of  the  whole  length  of  the  hemisphere. 
It  is  relatively  longer  and  more  curved  in  the  anthropoid  apes  than  in  man."  (See 
additional  measurements.) 

'2  Cunningham  (op.  cit.,  63)  found  a  connection  of  the  central  and  Sylvian  in  19  % 
of    hemispheres    (of    whites)  ;    Benedict   {Anat.    Studien    an     Verbrecher-Gehirnen, 


KISHU'S  CEREBRUM  (DORSAL  ASPECT) 


AN  ESKIMO  BRAIN  II 

of  the  central  fissure  is  situated  0.6  cm.  below  the  borders  of  the 
Sylvian  on  the  left,  and  1.5  cm.  on  the  right  It  nearly  connects 
on  the  right  with  the  superior  limiting  sulcus  of  the  insula.  A 
short  distance  above  the  Sylvian  border,  the  left  central  fissure 
shows  a  submerged,  but  not  very  deep,  annectent  gyrus;  on  the 
right  there  are  two  such  fascicles  in  a  similar  location. 

The  form  of  the  central  fissure  is  quite  tortuous,  especially  on 
the  right.  The  left  fissure,  neglecting  minor  bends,  is,  from 
above  downward  and  with  reference  to  the  frontal  lobe,  convex, 
concave,  convex,  concave,  much  convex,  and  nearly  straight ; 
that  on  the  right,  convex,  concave,  convex,  concave,  convex. 

Each  of  the  fissures  sends  a  number  of  incisures  into  the 
adjacent  convolutions.  On  the  right,  3.3  cm.  above  the  Sylvian, 
the  central  fissure  connects,  over  a  quite  superficial  annectent 
gyrus,  with  the  postcentral  sulcus.1 

The  two  fissures  show  no  submerged  interruption. 

The  superior  ends  of  the  central  fissures  are  situated  almost 
opposite;  distance  from  the  same  to  the  superior  border,  left,  0.5 
cm.  ;  right,  0.5  cm.2 

Additional  measures : 

Left  Right 

(i)  Origin  of  central  fissure  (on  the  lip  of  the  Syl- 
vian) to  frontal  pole  3 7.3  cm.  6.5  cm. 

(2)  Superior  extremity  of  central  fissure  to  frontal 

pole 10.9  cm.         10.8  cm. 

Wien,  1872,  p.  96)  found  a  complete  connection  in  18  and  an  incomplete  one  in  6  of 
38  hemispheres  examined.  Giacomini  (Varieta  d.  circonvoluzioni  cerebrali  dell'  uomo, 
Torino,  1882,  cited  by  Cunningham)  found  such  a  connection  only  in  21  among  336 
hemispheres.  Retzius  {Das  Menschengehirn,  1896,  I,  p.  100)  found  the  connection  in 
23  %  of  the  hemispheres  of  Swedes. 

1  Retzius  observed,  on  the  brains  of  whites,  anastomosis  of  the  Rolandic  fissure 
with  the  inferior  postcentral  sulcus  in  9  %,  with  the  superior  in  3  %  of  the  cases. 

2  Cunningham  (op.  cit. ,  p.  162),  in  52  hemispheres  of  white  children  and  adults, 
found  the  following  conditions  in  this  respect  :  "(a)  In  60  %  the  upper  end  of  the 
fissure  cut  the  upper  border  of  the  hemisphere  and  appeared  on  the  inner  surface  ;  (b) 
in  21  £  it  just  reached  the  upper  border  ;  and  (c)  in  19  %  it  fell  short  of  the  upper 
border." 

6  This  and  the  following  measures  are  the  horizontal  distances  between  vertical 
planes  at  the  points  mentioned. 


12  AN  ESKIMO  BRAIN 

Left  Right 

(3)  Origin  of  central  fissure  to  occipital  pole 10.7  cm.         11.4  cm. 

(4)  Superior  extremity  of  central  fissure  to   oc- 

cipital pole 7.1cm.  7.1cm. 

Reduced  to  per  cent,  of  the  total  antero-posterior  diameters 
of  the  hemispheres,  these  distances  are  : 

Left  Rigkt 

(1) 4°-6  ^         36-3$ 

(2) 60.6  <fo  60.4  <fo 

(3) 59-4  io         63.7  i 

(4) 39-4  i         39-6  i 

PARIETO-OCCIPITAL    FISSURE 

The  fissure  appears  on  both  sides  like  a  direct  and  equally  deep 
continuation  of  the  calcarine  stem.  It  runs  on  each  side,  in  nearly 
a  straight  line,  upward  and  slightly  backward  to,  and  on  the  left 
2.1  cm.,  on  the  right  1.5  cm.,  over,  the  superior  border  of  the 
hemisphere.  The  extremity  forms  on  each  side  a  small  T,  which 
is  surrounded  by  a  pronounced  paroccipital  gyrus. 

The  average  depth  of  the  fissure  is  2.3  cm.  on  the  left  and  2.3 
cm.  on  the  right  side ;  its  length,  from  its  junction  with  the  cal- 
carine stem  to  the  superior  border  is  on  the  left  4.0  cm.,  on  the 
right  4.2  cm. 

The  fissure  on  the  left  connects  over  a  submerged  but  quite 
superficial  gyrus  with  the  sub-precuneal  sulcus,  while  that  on  the 
right  shows  a  slightly  deeper  connection  with  a  sulcus  from  the 
cuneus. 

There  are  only  a  few  very  deep  annectent  bundles  within 
each  fissure. 

CALCARINE    STEM    AND    SULCUS 

The  stem  is  simple,  its  course  on  each  side  slightly  wavy.  Its 
length  is  2.6  cm.  on  the  left,  3.3  cm.  on  the  right ;  its  average 
depth  on  both  sides  about  1.5  cm.  ;  at  its  junction  with  the  pari- 
eto-occipital  it  equals  the  latter  in  depth. 

Both  calcarine  sulci  communicate  with  the  stem  over  a  sub- 
merged but  not   very   deep  gyrus.     The   left    sulcus   is    nearly 


AN  ESKIMO  BRAIN  I  3 

straight  ;  the  right  one  describes  anteriorly  a  moderate  curve. 
The  sulcus  on  the  left  is  free  from  connections  and  gives  off  but 
two  small  incisures  ;  that  on  the  right  connects  superficially  with 
a  cuneal  sulcus  and  sends  from  its  curve  a  deep  branch,  i.o  cm. 
long,  downward  to  the  basi-mesial  border. 

The  calcarine  sulcus  extends  on  both  sides  to  the  dorsal  sur- 
face of  the  occipital  lobe,  and  terminates  in  a  small  bifurca- 
tion. The  most  distal  point  is  on  the  left  1.55  cm.,  on  the  right 
1.3  cm.,  in  a  straight  line  beyond  the  border  of  the  hemisphere. 

The  length  of  the  calcarine  sulcus  from  its  junction  with  the 
stem  to  the  border  of  the  occipital  lobe  is  4.6  cm.  on  the  left,  4.8 
cm.  on  the  right  side.  It  is  on  both  sides  much  shallower  than 
the  stem. 

There  are  a  number  of  connecting  fasciculi  within  the  two 
calcarine  stems  and  sulci.  On  the  left  there  is  a  deep  bundle 
in  about  the  middle  of  the  stem  and  reaching  from  the  base 
of  the  stem  to  the  point  of  the  cuneus  ;  there  are  also  two  bundles 
at  medium  depth  behind  the  junction  of  the  stem  and  the  sulcus 
and  passing  from  the  gyrus  lingualis  to  the  cuneus  ;  and  there  is 
another  fascicle  of  medium  depth  in  the  sulcus,  about  2  cm.  from 
the  occipital  border.  On  the  right  side  we  find  similar  annectent 
gyri  in  similar  locations,  but  the  bundle  in  the  stem  passes  down- 
ward to  the  bottom  and  does  not  visibly  reach  the  cuneus. 

COLLATERAL    FISSURE 

This  furrow  is  of  considerable  extent,  particularly  on  the 
right.  Its  total  length,  in  a  straight  line,  is  8.15  cm.  on  the  left, 
and  1 1.3  cm.  on  the  right. 

The  anterior  termination  of  the  fissure  is  on  both  sides  free 
and  simple  ;  it  is  distant  from  the  pole  of  the  temporal  lobe  on 
the  left  5.7  cm.,  on  the  right  2.9  cm. 

On  both  sides,  nearly  in  the  line  of  continuation  of  the  collat- 
eral fissure  and  incising  the  antero-mesial  border  of  the  temporal 
lobe,  is  found  a  well-developed  fissura  rhinica.     This  furrow  is 


14  AN  ESKIMO  BRAIN 

particularly  marked  on  the  left  side  where  the  collateral  is 
shorter. 

Posteriorly,  the  left  collateral  fissure  terminates  in  a  line  about 
3  mm.  from  the  border  of  the  hemisphere,  while  on  the  right 
it  reaches  the  border.  Both  of  the  fissures  connect,  each  by  a 
shallow  sulcus,  with  the  third  temporal. 

Each  collateral  gives  off  several  incisures.  In  the  posterior 
half  of  both  fissures  are  found,  at  medium  depth,  annectent 
bundles  which  pass  between  the  fusiform  and  lingual  lobules. 

CALLOSO-MARGINAL    FISSURE 

The  gyration  on  the  mesial  surface  of  this  brain  presents 
several  very  interesting  modifications.  The  calloso-marginal  is 
duplicated  on  the  left  and  almost  triplicated  on  the  right  side. 
The  main  fissure  is  on  both  sides  throughout  continuous  and 
connects  freely  and  deeply  with  the  paracentral.  It  is  on  both 
sides  doubled  by  a  pronounced  mesial  frontal  sulcus.  This  is 
deep  and  continuous  on  the  left,  more  shallow  and  interrupted  by 
an  isthmus  on  the  right.  In  addition  the  right  callosal  gyrus  is 
traversed  along  its  entire  superior  extent  by  a  shallow,  inter- 
rupted sulcus,  which  runs  parallel  with  the  calloso-marginal  fissure 
and  separates  the  surface  of  the  callosal  into  two  nearly  equal 
superior  and  inferior  portions. 

The  left  calloso  marginal  begins  in  a  simple  way  below  the 
genu  of  the  callosum  ;  the  right  proceeds  from  a  subrostral  sulcus 
which  curves  about  a  lobule  on  the  posterior  extremity  of  the 
mesial  portion  of  the  frontal  lobe. 

During  its  course,  each  of  the  calloso-marginal  fissures  gives  off 
a  few  small  branches  or  incisures.  On  the  left,  as  well  as  on  the 
right,  four  such  small  branches  indent  the  superimposed  part  of 
the  superior  frontal  gyrus. 

There  is  on  both  sides  a  well-developed  rostral,  and  on  the 
right  also  a  transverse  subrostral  sulcus  ;  there  is  also  a  fair  repre- 
sentation on  each  side  of  the  postlimbic  sulcus. 


PLATE  III 


KlSHU'S  CEREBRUM   (BASA^.  ASPECT) 


AN  ESKIMO  BRAIN  I  5 

The  paracentral  sulci  are  well  curved  and  both  end  on  the 
dorsal  surface  of  the  hemisphere  :  the  left  in  a  line,  1.5  cm.  from 
the  median  border  and  0.7  cm.  behind  the  superior  extremity  of 
the  central  fissure ;  the  right  in  a  T,  with  the  posterior  branch 
much  shorter  than  the  anterior,  1.6  cm.  from  the  median  border 
of  the  hemisphere  and  0.5  cm.  behind  the  terminus  of  the  central 
fissure. 

The  average  depth  of  the  calloso-marginal  is  1.0  cm.  on  the 
left,  1.3  cm.  on  the  right ;  that  of  the  paracentral  1.5  cm.  on  the 
left  and  1.8  cm.  on  the  right  side. 

Annectent  Gyri. — There  are  in  the  calloso-marginal  five  or  six 
deep  bundles  on  the  left  and  seven  or  eight  such  bundles  on  the 
right,  passing  between  the  callosal  gyrus,  the  superior  frontal 
convolution,  and  the  paracentral  lobule. 

MINOR    FISSURES    OR    SULCI 

Frontal  Lobe. — The  superior  frontal  sulcus  on  the  left  is  a  con- 
tinuous furrow,  which  runs,  in  a  tortuous  way,  from  the  anterior 
portion  of  the  orbital  surface  to  within  a  few  millimeters  of  the 
superior  precentral  sulcus.  On  the  right  a  similar  but  somewhat 
less  tortuous  furrow  extends  from  the  orbital  border  of  the 
frontal  lobe  to  the  superior  precentral  sulcus,  connecting  with 
the  same. 

Each  of  the  sulci  sends  off  a  number  of  transverse  branches 
and  incisures.  That  on  the  left  communicates  with  the  medial 
frontal  sulcus  of  Eberstaller  and  with  the  vertical  furrow  anterior 
to  the  precentral  sulci ;  that  on  the  right  connects  with  the 
medial  frontal  and  the  superior  precentral  sulcus. 

The  depth  of  each  of  the  superior  frontal  sulci  averages  about 
1.5  cm.,  the  maximum  depth  measured  being  2.8  cm.  (on  the 
left). 

Mesially  from  the  superior  frontal  sulci  we  find  on  each  side 
of  the  brain,  but  particularly  on  the  left,  small  segments  of  Cun- 
ningham's mesial  sulcus. 


1 6  AN  ESKIMO  BRAIN 

The  medial  frontal  sulci  of  Eberstaller  are  only  fairly  well 
represented. 

The  inferior  frontal  sulcus  can  be  isolated  with  more  facility 
on  the  left  than  on  the  right  hemisphere ;  it  does  not  connect  on 
either  side  with  the  inferior  precentral  sulcus. 

The  left  inferior  frontal  sulcus  is  in  two  portions;  it  begins 
posteriorly  3  mm.  in  front  of  the  middle  of  the  inferior  precentral, 
intersects  the  anomalous  vertical  furrow,  and  terminates  about 
2  cm.  in  front  of  this  furrow  in  a  shallow  Y.  A  few  millimeters 
inferiorly  and  posteriorly  to  the  lower  terminal  branch  of  this  Y 
begins  the  second  portion  of  the  sulcus.  This  portion  consists 
mainly  of  the  sulcus  radiatus,  and  sends  six  branches  into  the 
adjacent  convolutions. 

On  the  right  side,  that  part  of  the  vertical  furrow  which  cor- 
responds to  the  diagonal  sulcus  connects,  1.9  cm.  above  the 
Sylvian,  with  a  short  but  deep  T  branch,  1.0  cm.  long,  which  runs 
directly  forward  and  probably  represents  the  posterior  extremity 
of  the  inferior  frontal  sulcus.  The  anterior  portion  of  the  same 
consists  of  the  sulcus  radiatus,  possibly  joined  with  the  fronto- 
marginal  sulcus.  This  portion,  as  on  the  left,  shows  six 
branches.  One  of  these  connects  inferiorly  with  the  anterior 
branch  of  the  presylvian ;  another  ascends  to  within  a  short  dis- 
tance of  the  median  frontal  sulcus. 

A  small  independent  depression  indents  on  each  side  the  sur- 
face of  the  pars  triangularis  of  the  inferior  frontal  gyrus. 

All  the  frontal  sulci  show  numerous  submerged  annectent 
gyri. 

The  anomalous  vertical  furrow  which  runs  on  each  side  an- 
terior to  and  nearly  parallel  with  the  precentral  sulci,  has  been 
referred  to  in  the  description  of  the  Sylvian. 

The  precentral  sulcus  consists  on  each  side  of  two  independent, 
radiating  segments  of  considerable  depth.  On  the  left  these 
segments  are  isolated ;  on  the  right  the  superior  connects,  over  a 
deep  annectent  bundle,  with  the  first  frontal  sulcus,  while  the 


AN  ESKIMO  BRAIN  I  7 

inferior  joins  and  probably  forms  the  superior  part  of  the 
anomalous  vertical  furrow. 

Above  the  superior  precentral  there  is  on  each  side  an  inde- 
pendent, triradiate  sulcus  extending  to  the  upper  border  of  the 
hemisphere  and  bounding  laterally  the  ascending  frontal  con- 
volution ;   it  looks  like  a  third  part  of  the  precentral. 

Orbital  Surface. — The  Sulcus  Olfactorius  presents  a  typical 
conformation.  It  is  a  long  depression,  running  from  i.o  cm. 
at  base  to  0.5  cm.  at  terminus  laterally  to  the  median  fissure, 
quite  deep,  terminating  on  the  left  side  in  a  free  line  and 
on  the  right  side  in  a  small  Y.  Slightly  anteriorly  to  the  end  a 
small  transverse  sulcus  crosses  the  border  of  the  hemisphere  on 
the  left,  and  a  small  semicircular  sulcus  indents  the  border  on  the 
right  side.  The  parts  of  the  first  frontal  gyrus  traversed  by  the 
olfactory  sulcus  are,  as  previously  stated,  quite  prominent. 

Besides  the  olfactory,  each  of  the  orbital  parts  shows  two 
other  antero-posterior  sulci.  One  of  these,  the  outer,  is  apparently 
the  orbital  sulcus.  Its  form  on  the  left  is  that  of  a  Y,  or  of  a  K 
with  the  lower  branch  interrupted,  while  on  the  right  side  it 
forms  a  somewhat  crooked  X. 

Both  of  these  figures  are  situated  somewhat  more  externally 
than  is  usual,  and  between  them  and  the  olfactory  furrows  we 
find  on  each  side  a  distinct  separate  sulcus.  On  the  left  this 
sulcus  consists  of  two  branches  and  indents  the  first  frontal  con- 
volution. The  anterior  branch  communicates  with  the  main 
ramus  of  the  orbital  sulcus.  On  the  right  side  the  sulcus  begins 
near  the  root  of  the  olfactory  nerve  and  then  passes  forward, 
bounding  the  first  frontal  gyrus. 

The  transverse  orbital  sulci  present  nothing  extraordinary. 

Parietal  Lobe. — The  postcentral  sulcus  shows  neither  on  the 
left  nor  on  the  right  any  superficial  interruption.1    It  connects  on 

1  According  to  Cunningham,  in  the  brains  of  adult  Irishmen  the  postcentral 
sulcus  was  found  complete  and  separated  from  the  interparietal  sulcus  (as  on  the  right 
in  the  Eskimo  brain)  in  11?;  it  was  found  complete  and  communicating  with  the 
interparietal  (as  on  the  left  in  the  Eskimo  brain)  in  60  %  of  the  hemispheres. 


1 8  AN  ESKIMO  BRAIN 

both  sides  with  the  Sylvian  and  on  the  left  side  also  with  the 
interparietal  sulcus. 

The  left  postcentral  is  very  long,  reaching  to  within  0.5  cm. 
of  the  superior  border  of  the  hemisphere,  where  it  connects,  over 
an  imperfectly  submerged  gyrus,  with  a  vertical  sulcus  from  the 
precuneus. 

The  connection  of  the  postcentrals  with  the  Sylvian  is  not 
effected  by  the  trans- postcentral  sulci. 

The  course  of  both  postcentral  sulci,  and  particularly  of  that 
on  the  left,  is  tortuous. 

Each  sulcus  gives  off  during  its  course  several  incisures  and 
small  branches.  On  the  left  side,  1.4  cm.  above  the  Sylvian  bor- 
der, a  quite  deep  branch  passes  backward  through  the  supra- 
marginal  convolution  and  communicates  with  the  superior 
terminal  branch  of  the  Sylvian.  Three  cm.  above  the  Sylvian 
the  left  postcentral  connects,  over  a  submerged  gyrus,  with  the 
interparietal  sulcus.  Opposite  this  junction  a  branch,  1.4  cm.  long 
and  looking  like  the  anterior  terminus  of  the  interparietal,  passes 
forward  and  slightly  upward  into  the  ascending  parietal  gyrus. 

In  its  upper  third  the  left  retrocentral  sulcus  gives  off  three 
smaller  branches.  The  lowest  one  of  these  passes  backward  ;  the 
middle  one  indents  the  ascending  parietal  gyrus  and  ends  near 
the  central  sulcus ;  the  third  branch  passes  upward,  ending  in 
front  of  the  dorsal  termination  of  the  paracentral  fissure.  The 
main  limb  of  the  sulcus  then  bends  backward  and  runs  toward 
the  aforementioned  connection  with  the  precuneal. 

The  right  postcentral  sends  off  four  branches  or  incisures, 
one  of  which,  2.0  cm.  long,  passes  backward  from  near  the  mid- 
dle of  the  sulcus.  Two  and  a  half  cm.  above  the  Sylvian  the 
right  postcentral  connects,  over  a  submerged  but  not  deep 
fascicle,  with  the  central  fissure. 

Superiorly  the  sulcus  divides  into  two  branches,  the  anterior 
1.4  cm.,  the  posterior  2.4  cm.  in  length,  which  surround,  in  the 
form  of  a  broad  Y,  the  extremity  of  the  paracentral  sulcus. 


PLATE  IV 


ri  /  ■■: 


Lateral  aspect 


Mesial  aspect 
THC  HEMISPHERES  OF  KISHU'S  CEREBRUM 


AN  ESKIMO   BRAIN 


19 


Each  postcentral  shows  in  its  course  a  number  of  more  or  less 
deep  annectent  fascicles. 

The  trans-postcentrals  are  in  their  usual  position,  but  only 
that  on  the  left  (as  was  the  case  with  the  trans-precentrals)  reaches 
the  dorsal  surface  of  the  hemisphere. 

The  interparietal  sulcus  on  the  left  commences,  with  a  small  T, 
somewhat  inferiorly  and  anteriorly  to  the  end  of  the  superior 
terminal  Sylvian,  1.8  cm.  from  the  Sylvian  bifurcation.  Seven 
millimeters  above  its  beginning  the  sulcus  connects,  over  a  sub- 
merged but  not  deep  gyrus,  with  the  postcentral.  From  this 
point  the  interparietal  runs  in  a  slight  curve  4.2  cm.  upward  and 
backward  and  joins  freely  the  paroccipital  sulcus.  The  inter- 
parietal gives  off  three  larger  branches,  one  of  which  runs  down- 
ward, into  the  supramarginal,  and  the  other  two  upward,  into  the 
superior  parietal  gyrus.  There  are  within  the  sulcus  several  deep 
but  no  interrupting  connecting  bundles. 

On  the  right  side  we  find  an  anomalous  deep  furrow,  uninter- 
rupted except  by  very  deep  bundles,  running  from  a  point  well 
down  between  the  supramarginal  and  angular  gyri,  in  a  wavy 
course,  parallel  in  the  main  with  that  of  the  postcentral  sulcus 
and  central  fissure,  to  and  1.0  cm.  over  the  superior  border  of  the 
hemisphere,  ending  on  the  precuneus. 

From  this  furrow,  above  its  middle,  begins,  over  a  depressed 
but  still  partly  visible  gyrus,  the  horizontal  part  of  the  inter- 
parietal. This  is  angular,  but  0.8  cm.  long  (in  a  straight  line),  and 
connects  with  the  paroccipital. 

The  vertical  furrow  separates  a  stout  and  prominent  con- 
volution which  runs  parallel  with  the  ascending  frontal  and 
ascending  parietal  gyri.  The  superior  portion  of  the  vertical 
furrow  lies,  independent  of  both,  between  the  postcentral  and  the 
anterior  curve  of  the  paroccipital  sulcus. 

The  minor  parietal  sulci  will  be  mentioned  with  the  descrip- 
tion of  the  convolutions. 

Occipital  Lobe. — The  anterior  as  well  as  the  lateral  occipital 


20  AN  ESKIMO  BRAIN 

sulcus  is  fairly  well  represented  on  both  sides.  The  anterior 
sulcus  on  the  left  connects  with  the  ascending  branch  of  the 
superior  temporal,  the  anterior  and  lateral  furrows  on  the  right 
with  the  anomalous  medio-temporal  sulcus  (q.  v.).  The  lateral 
sulcus  on  the  left  is  in  the  form  of  an  H  and  is  without 
connections. 

Temporal  Lobe. — The  sulci  on  the  superior  or  intrasylvian  sur- 
face of  the  lobe  have  been  mentioned. 

The  lateral  surface  is  higher  on  the  right  than  on  the  left  side. 
Its  sulci  are  on  both  sides  deep  and  the  gyrations  distinct. 

The  superior  or  first  temporal  sulcus  begins  on  both  sides 
in  a  line  near  the  pole  of  the  temporal  lobe.  It  is  preceded  on 
the  left  by  a  small  transverse  furrow,  on  the  right  by  a  shallow 
depression. 

The  horizontal  portion  of  the  superior  temporal  is  continuous  on 
both  sides.  Its  form  is  wavy  on  the  left,  more  straight  on  the  right 
side.  It  terminates  on  the  left  in  a  line  1.8  cm.  posteriorly  to  the 
Sylvian  bifurcation  and  within  0.3  cm.  of  the  inferior  terminal 
Sylvian.  The  ascending  portion  is  separate.  On  the  right  the 
horizontal  portion  runs  to  a  point  about  1.2  cm.  posterior  to  the 
Sylvian  bifurcation,  connects  with  the  inferior  terminal  Sylvian, 
and  proceeds  without  interruption  backward  and  upward  as  the 
ascending  ramus. 

The  horizontal  portion  on  the  left  connects,  1.6  cm.  before  its 
posterior  end,  over  a  submerged  but  not  deep  gyrus,  with  a 
parallel,  medio-temporal1  sulcus,  4.4  cm.  long,  which  separates  the 
posterior  half  of  the  middle  temporal  gyrus  into  an  inferior  and 
a  superior  portion.  The  horizontal  branch  on  the  right  connects, 
by  means  of  a  shallow  transverse  sulcus,  with  the  second  tem- 
poral, and  more  posteriorly  as  well  as  quite  superficially  with  the 
medio-temporal. 

The  ascending  branch  on  the  left  begins  with  a  short  vertical 

1  This  term  suggests  itself  from  some  similarity  of  this  to  the  medio-frontal  sulcus 
of  Eberstaller. 


AN  ESKIMO   BRAIN  21 

part  that  connects  with  the  inferior  terminal  Sylvian.  It  runs 
backward  and  slightly  upward,  almost  in  line  with  the  horizontal 
portion.  It  connects  with  the  ascending  part  of  the  second  tem- 
poral, and  finally  joins  the  anterior  occipital  sulcus. 

On  the  right  the  ascending  branch  runs  in  an  angular  manner 
upward  and  backward,  terminating  a  short  distance  below  the 
paroccipital.  This  branch  also  has  a  shallow  connection  with  the 
mcdio-temporal. 

The  mcdio-temporal  sulcus  is  even  better  marked  on  the  right 
than  on  the  left.  Beginning  somewhat  posteriorly  to  a  vertical 
from  the  Sylvian  bifurcation,  it  runs  backward  and  upward, 
parallel  with  the  ascending  portion  of  the  first  temporal,  to  the 
occipital  lobe.  It  connects  with  both  the  horizontal  and  ascend- 
ing portions  of  the  first  temporal  and  also  with  the  anterior  as 
well  as  with  the  lateral  occipital  sulci. 

Both  the  first  and  the  medio-temporal  sulci  send  off  shorter 
branches  and  all  show  deep  connections  passing  between  the 
adjacent  gyri. 

The  mean  depth  of  the  horizontal  ramus  of  the  left  superior 
temporal  sulcus  is  1.8  cm.,  that  of  the  right,  2.1  cm.  The  ascend- 
ing rami  are  not  so  deep.  The  depth  of  the  me dio-temp orals  is 
less  than  that  of  the  horizontal,  but  slightly  greater  than  that  of 
the  ascending  portion  of  the  first  temporal  sulci. 

The  second  or  middle  temporal  sulcus  is  composed  on  each  side 
of  two  separate  segments ;  each  of  these  shows  some  secondary 
ramifications. 

The  anterior  portion  on  the  left  commences  with  a  curve, 
passes  in  a  wider  curve  backward  and  slightly  upward,  and  ter- 
minates, nearly  vertically  below  the  central  fissure,  with  several 
marked  radiations.  The  posterior  left  segment  begins  in  a  Y 
slightly  above  and  posteriorly  to  the  termination  of  the  first  part, 
and  runs  slightly  downward  and  backward,  to  and  along  the  in- 
ferior border  of  the  hemisphere,  terminating  in  a  simple  manner 
about  1.6  cm.,  in  a  straight  line,  from  the  occipital  pole,  under  the 


22  AN  E SKIMO  BRAIN 

lateral  occipital  sulcus.  Two  and  seven-tenths  of  a  cm.  anteriorly 
to  its  end  this  segment  gives  off,  over  a  deep  annectent  fascicle, 
an  ascending  portion,  which  runs  with  several  bends  directly  up- 
ward to  connect  with  the  ascending  part  of  the  first  temporal 
sulcus. 

On  the  right  side,  the  first  portion  of  the  second  temporal  has 
its  simple  beginning  i.o  cm.  in  a  straight  line  from  the  pole  of 
the  temporal  lobe  ;  it  passes  4.6  cm.  backward  and  ends  in  a 
small  bifurcation.  A  short  distance  anteriorly  to  this  bifurcation 
the  sulcus  communicates  with  the  first  temporal. 

The  posterior  segment  on  the  right  begins  a  little  posteriorly 
to  the  bifurcation  of  the  first  part,  in  the  form  of  a  doubly  curved, 
nearly  transverse  line.  This  line  bends,  runs  backward  and  down- 
ward, reaches  the  inferior  border,  sends  a  1.3  cm.  long  branch 
backward  and  inward  into  the  third  temporal  gyrus,  passes  again 
to  the  dorsal  surface  of  the  hemisphere,  and  ends  in  a  long  Y 
figure,  the  lower  extremity  of  which  reaches  to  below  the  lateral 
occipital  sulcus. 

The  third  or  basitemporal  sulcus  is  unusually  well  developed, 
particularly  on  the  left  side. 

The  sulcus  on  the  left  is  continuous,  somewhat  wavy  in  form, 
and  measures  9.3  cm.  in  length  (in  a  straight  line).  It  effects 
a  shallow  connection  with  the  collateral. 

The  right  sulcus  consists  of  three  large  separate  segments, 
which  extend  from  near  the  pole  of  the  temporal  lobe  to  within 
1.7  cm.  of  the  occipital  pole.  The  segments  send  off  a  number 
of  radiating  branches,  and  the  posterior  one  connects  with  the 
collateral. 

On  both  sides  the  third  temporal  sulcus  contains  a  number  of 
submerged,  more  or  less  deep,  annectent  fascicles. 

THE   INSULA 

The  conformation  of  the  surface  of  the  island  is  quite  similar 
on  the  two  sides  of  the  brain  (figs.  57,  58). 


AN  ESKIMO   BRAIN 


23 


Fig.  17 — Left  insula.  S.L.S.,  S.L.A.,  S.L.P.,  Sulci  limitantes 
insula;,  superior,  anterior,  posterior;  S.C.I..  Sulcus  centralis 
insulae  ;  S.P-c.  I.,  Sulcus  post-centralis  insulae. 


The  marginal  or  limiting  sulci  of  the  insula  are  very  deep, 
especially  anteriorly,  and  they  are  continuous,  except  over  the 
antero- inferior  ex- 
tremity or  pole  of 
the   insula. 

The  superior 
limiting  sulcus  com- 
municates on  both 
sides  with  the  two 
branches  of  the  pre- 
sylvian;  it  also  gives 
off  on  each  side  two 
short  branches  up- 
ward, and  a  deep 
short  incisure  down- 
ward, into  the  insula 
itself.  The  average 
depth  of  the  su- 
perior limiting  sulci 
is  2.8  cm.,  and  in  the 
course  of  each  there 
are  several  strong 
annectent  fascicles 
passing  between  the  lobes  of  the  island  and  the  overlying 
opercula. 

At  the  posterior  inferior  angle  of  the  insula  there  are  two  strong, 
almost  superficial  annectent  bundles,  connecting  the  superior  tem- 
poral gyrus  with  the  insula ;  there  is  on  each  side  also  a  strong 
connecting  bundle  between  the  anterior  extremity  of  the  posterior 
lobe  of  the  insula  and  the  superior  temporal  convolution. 

The  central  sulcus  of  the  insula  is  independent  on  the  left, 
but  it  communicates  with  the  superior  limiting  sulcus  on  the 
right  side.  The  central  sulci  average  only  0.5  cm.  in  depth,  and 
each  shows  anteriorly  a  submerged  anastomotic  fascicle. 


Fig.  28— Right  insula.  P-s.A.,  Presylvian  anterior;  P-s.P.,  Pre- 
sylvian  posterior  ;  S.D.,  Sulcus  diagonalis  ;  a,  Trans-precen- 
tral  sulcus  ;  F.C.,  Central  fissure  ;  b,Trans-postcentral  sulcus  ; 
c.  Postcentral  sulcus. 


24  AN  ESKIMO  BRAIN 

Besides  the  above  sulci,  each  insula  shows  a  small  furrow 
which  divides  its  posterior  lobe  into  superior  and  inferior  por- 
tions (sulci  retrocentrales  insulae).  There  is  also  on  each  side 
a  curving  but  not  very  deep  sulcus  which  passes  from  below  over 
the  pole  of  the  insula.  This  sulcus  ends  freely  on  the  anterior 
lobule  of  the  insula  on  the  right,  but  joins  the  anterior  limiting 
sulcus  on  the  left  side. 

The  anterior  and  posterior  lobes  of  the  insula  are  well  defined 
and  show  the  ordinary  planes.     Gyri  breves  fairly  well  marked. 

CONVOLUTIONS 

Frontal  Lobe.  Dorsal  Surface. — The  frontal  gyri  are  rather 
more  complex  and  tortuous  than  in  average  whites.  The  dorsal 
portion  of  the  left  superior  frontal  gyrus  is  slightly  narrower  in 
front  than  that  of  the  right  (left  2.85  cm.,  right  3.05  cm.),  but 
somewhat  broader  posteriorly  (left  2.8  cm.,  right  2.5  cm.).  In 
about  the  middle,  the  left  gyrus  sends  downward  a  prominent, 
shoe-like  convolution,  which  indents  the  middle  frontal  gyrus. 
The  dorsal  parts  of  both  superior  frontal  convolutions  show,  be- 
sides the  segments  of  the  sulcus  mesialis  of  Cunningham,  a  con- 
siderable number  of  transverse  depressions. 

The  middle  or  second  frontal  gyrus  is  on  both  sides  of  an 
irregular  form  and  partly  subdivided  by  the  medial  frontal  sul- 
cus. The  posterior  portion  of  the  convolution  on  the  left  is  es- 
pecially well  developed,  and  is  separated  from  the  more  anterior 
portion  by  the  vertical  furrow.  Both  middle  frontal  gyri  have 
numerous  superficial  and  deep  connections  with  the  neighboring 
convolutions. 

The  inferior  or  third  frontal  gyrus  is  in  this  brain,  contrary 
to  the  general  rule,  more  extended  antero-posteriorly  and  more 
redundant  on  the  right  than  on  the  left  side.  This  excess  is 
especially  marked  in  the  right  middle  or  triangular  part  (cap  of 
Broca). 

The  convolution  shows  numerous  connections  ;  the  orbital  and 


AN  ESKIMO   BRAIN  2$ 

triangular  parts  connect  on  both  sides  superficially  with  the  middle 
frontal  gyrus. 

The  ascending  frontal  convolution  is  somewhat  stronger  on  the 
right  than  on  the  left.  It  is  on  both  sides  most  slender  in  its 
middle  fourth.  It  is  on  both  sides  continuous  from  the  Sylvian 
fissure  to  the  superior  border  of  the  hemisphere.  Superficial  con- 
nections.— On  the  left :  a  broad  isthmus  to  the  inferior  frontal ; 
a  superficial  annectent  gyrus  to  the  middle  frontal ;  similar  gyrus 
to  superior  frontal  ;  and,  at  the  median  border  of  the  hemisphere, 
three  superficial  annectent  gyri,  one  to  the  superior  frontal,  one 
to  the  paracentral,  and  one  to  the  ascending  parietal  convolu- 
tions. On  the  right  there  is  a  broad  superficial  connection  with 
the  pars  basilaris  of  the  inferior  frontal;  and  similar  connections 
anteriorly  with  the  middle  and  superior  frontal,  and  superiorly 
with  the  paracentral  and  ascending  parietal  gyri. 

Mesial  Surface. —  The  left  marginal  gyrus  is  considerably 
higher  than  the  right  one.  Its  height  is,  from  the  orbital  surface 
to  the  calloso-marginal  fissure,  on  the  left  2.2  cm.,  on  the  right 
1.8  cm. ;  opposite  the  anterior  pole,  on  the  left  3.2  cm.,  on  the 
right  2.5  cm. ;  and  the  average  height  of  the  upper  part  is,  on  the 
left  2.6  cm.,  on  the  right  2.3  cm.  On  both  sides  the  marginal  and 
the  calloso-marginal  gyri  stand  to  each  other,  as  to  size,  in  an  in- 
verse relation. 

The  inferior  extremity  of  each  marginal  gyrus  is  marked  by 
the  sulcus  rostralis  transversus  and  connects  almost  superficially 
with  the  inferior  extremity  of  the  limbic  lobe  (carrefour  olfactif 
of  Broca).  The  posterior  extremity  of  the  marginal  gyrus  com- 
municates on  the  left  by  two  superficial,  on  the  right  by  one 
superficial  and  one  deep,  annectent  gyri  with  the  paracentral 
lobule. 

As  to  the  convolutions  on  the  orbital  surface  of  the  frontal 
lobes,  on  the  left  the  first  and  third  frontal  gyri,  both  markedly 
developed,  join  a  little  posterior  to  the  middle  of  the  surface,  and 


26  AN  ESKIMO  BRAIN 

the  second  frontal  gyrus  forms  a  wedge  anteriorly  between  them. 
On  the  right,  the  second  passes  between  the  first  and  third  gyri 
as  a  narrow  band  to  the  root  of  the  olfactory  nerve,  where  it  joins 
the  extremities  of  the  other  frontal  convolutions. 

The  olfactory  tracts  and  bulbs  show  nothing  unusual. 

The  Parietal  Lobe. — The  ascending  parietal  gyrus  is  somewhat 
more  voluminous  on  the  left  hemisphere  (average  width  on  the 
left  about  1.2  cm.,  on  the  right  about  1.0  cm.).  The  base  of  the 
convolution  on  the  left  measures,  antero-posteriorly,  3.2  cm.,  of 
that  on  the  right  1.9  cm.  Both  gyri  show  a  constriction  between 
their  lower  and  middle  thirds,  and  a  marked  development  of  the 
latter  portion.  The  upper  third  is  on  each  side  slender,  tapering, 
and  not  raised  fully  to  the  niveau  of  the  neighboring  parts. 

The  upper  extremity  of  the  gyrus  connects  superficially  with 
the  ascending  frontal,  paracentral,  and  superior  parietal  convolu- 
tions ;  the  lower  part  connects,  by  means  of  submerged  but  not 
deep  fascicles,  with  the  ascending  frontal  and  supramarginal  gyri. 

The  superior  parietal  gyrus  is  throughout  somewhat  larger  on 
the  left  side.  Anteriorly  it  communicates  on  both  sides  super- 
ficially with  the  ascending  parietal,  and  in  a  similar  way  posteriorly 
with  the  superior  occipital  convolution.  Inferiorly  there  are  nu- 
merous submerged  fascicles  of  connection  between  the  superior 
and  inferior  parietal  gyri. 

The  left  superior  parietal  convolution  is  separated  by  trans- 
verse sulci  into  two  parts,  the  middle  of  which  is  very  redundant. 
The  right  gyrus  is  somewhat  similarly  divided  into  two  portions, 
of  which  the  anterior  is  the  more  redundant. 

The  convolution  shows  on  each  side  a  number  of  lateral  and 
surface  indentures. 

The  paroccipital gyrus  forms  on  each  side  a  well-marked  loop, 
which  surrounds  the  extremity  of  the  parieto-occipital  fissure. 
The  left  gyrus  is  larger  than  the  right  one. 

The  inferior  parietal  convolution  as  a  whole  is  larger  on  the 


AN   ESKIMO  BRAIN  27 

right,  compensating  for  the  smaller  size,  on  that  side,  of  the  supe- 
rior parietal. 

The  supramarginal gyrus  is  fairly  well  defined  on  the  left  and  is 
divided  from  the  angular  gyrus  by  a  vertical  branch  proceeding 
from  the  interparietal  sulcus  (the  sulcus  intermedius  primus,  Jen- 
sen, Eberstaller).  On  the  right  side  the  marginal  convolution  is 
larger  and  more  redundant ;  its  operculum,  or  the  triangular 
part  between  the  two  terminal  branches  of  the  Sylvian  fissure,  is 
especially  well  developed.  The  gyrus  is  bounded  posteriorly  by 
the  inferior  extremity  of  the  vertical  parietal  sulcus. 

The  angular  and  postparietal  gyri  are  nicely  differentiated 
loops,  separated  by  a  vertical  depression  (sulcus  intermedius 
secundus,  Eberstaller)  on  the  left,  but  are  of  irregular  form  and 
separated  only  from  below  by  the  extremity  of  the  ascending 
branch  of  the  superior  temporal  sulcus  on  the  right  side. 

All  the  parts  of  the  inferior  parietal  convolutions  show  minor 
lateral  or  surface  indentations,  and  numerous  deep  as  well  as 
superficial  connections. 

The  paracentral  lobule  is  much  better  isolated  anteriorly  on 
the  left  than  on  the  right.  The  left  lobule  is  also  slightly  more 
redundant,  though  slightly  less  high  and  not  any  longer  than  that 
on  the  right  side. 

The  surface  of  the  left  lobule  is  indented  by  two  Y-shaped  and 
one  lineal,  that  of  the  right  by  one  Y-shaped  and  two  lineal,  sulci. 

Precuneus. — This  lobule  is  separated  completely  on  the  left, 
incompletely  on  the  right,  from  the  limbic  gyrus,  by  the  posterior 
limbic  or  subprecuneal  sulcus.  The  surface  of  the  left  precuneus 
is  indented  by  four  vertical  sulci,  two  of  which  connect  with  the 
posterior  limbic,  while  the  other  two  pass  over  the  border  of  the 
hemisphere,  where  the  anterior  communicates  with  the  posterior 
terminal  branch  of  the  postcentral  sulcus,  and  the  posterior  one 
forms  the  anterior  boundary  of  the  paroccipital  gyrus.  On  the 
right,  the  precuneus  presents  a  Y-shaped   sulcus  in  connection 


28  AN  E  SKI  MO  BRA  IN 

with  the  intralimbic  and  postlimbic  sulci,  while  its  superior 
portion  is  indented  by  the  terminus  of  the  anomalous  vertical 
parietal  sulcus. 

Both  the  paracentral  lobule  and  the  precuneus  show  numerous 
deep,  besides  the  superficial,  connections  with  the  adjacent  gyri. 

Occipital  Lobe. — The  lobe  measures,  from  the  anteroinferior 
extremity  of  the  cuneus  to  the  occipital  pole,  on  the  left  4.7  cm., 
on  the  right  4.9  cm.,  which  is  respectively  26.1  %  and  27.4$  of 
the  whole  length  of  the  hemisphere  (see  also  additional  measures). 

The  gyration  of  the  lobe  in  the  Eskimo  brain  under  con- 
sideration is  not  inferior  to  that  met  ordinarily  in  whites.  It 
presents,  as  is  often  the  case,  some  difficulty  to  analysis,  but  no 
very  extraordinary  features. 

The  cuneus -is  bounded  by  almost  straight  lines.  It  is  lower, 
but  longer,  on  the  right  hemisphere.  Its  superior  border  is  in- 
dented on  the  left  by  two,  on  the  right  by  one  incisure.  Its  sur- 
face shows  on  the  left  an  independent  triradiate  sulcus  with 
branching  extremities  ;  on  the  right  a  large,  somewhat  Y-shaped 
sagittal  sulcus,  which  connects  with  the  parieto-occipital,  and  a 
quadriradiate  sulcus,  one  of  whose  branches  connects  with  the 
collateral. 

Temporal  Lobe. — The  superior  temporal  gyrus  is  considerably 
stronger  on  the  right  than  on  the  left  side  (mean  height  of  the 
left,  0.8  cm. ;  of  the  right,  1. 1  cm.).  The  left  gyrus  is  particularly 
slender  and  is  slightly  depressed  in  its  middle. 

The  left  convolution  is  interrupted  by  one  of  the  transtem- 
poral  furrows  which  connects  with  the  superior  temporal  sulcus. 

The  right  superior  temporal  gyrus  appears  to  be  composed 
of  three  imperfectly  separated  portions,  namely,  a  long  anterior 
part,  reaching  to  within  1.0  cm.  of  the  bifurcation  of  the  Sylvian, 
separated  from  the  rest  of  the  gyrus  by  two  incisures  (one 
superior  and  one  inferior),  which  almost  meet,  and  a  shallow  de- 
pression.    The  more  anterior  of  the  following  two  parts  is  in  the 


AN  ESKIMO   BRAIN 


29 


form  of  a  larger  oblong  lobule,  situated  between  the  depression 
just  mentioned  and  the  connection  of  the  inferior  terminal  Sylvian 
with  the  superior  temporal  sulcus.  The  third  part  is  a  small, 
partly  depressed  isle  projecting  from  the  second  part  into  the 
Sylvian  and  separated  from  that  part  by  a  shallow  sulcus. 

The  middle  or  second  temporal  gyrus  is  also  more  voluminous 
on  the  right  side  ;  both  are  quite  redundant. 

The  anterior  half  of  the  convolution  on  the  left  is  curved,  on 
the  right  straight  and  wedge-shaped.  The  posterior  half  on  each 
side,  somewhat  less  redundant,  is  divided  into  two  parallel, 
nearly  equally  strong  portions  by  the  secondary  medio-temporal 
sulcus. 

The  anterior  portion  of  the  right  gyrus  is  indented  by  two 
vertical  sulci  proceeding  from  the  second  temporal ;  the  anterior 
of  these  connects  with,  while  the  posterior  reaches  very  near  to, 
the  first  temporal  sulcus. 

The  superior  posterior  portion  of  the  right  gyrus  is  separated 
by  a  connecting  branch  between  the  first  and  medio-temporal 
sulci. 

Both  gyri  show  a  number  of  more  or  less  marked  lateral  in- 
cisures and  a  few  minor  surface  furrows. 

The  inferior  or  third  temporal  gyrus  lies,  on  both  sides  of  this 
Eskimo  brain,  almost  wholly  on  the  inferior  surface  of  the  tem- 
poral lobe.     It  is  easily  isolated. 

The  gyrus  is  on  both  sides  strongest  in  about  its  middle  third, 
its  anterior  and  posterior  extremities  tapering  a  little.  It  is  on 
each  side  incised  by  a  number  of  incisures  which  pass  into  it 
from  both  the  second  and  third  temporal  sulci,  but  it  is  nowhere 
totally  interrupted.  In  its  middle  enlargement  the  gyrus  is  on 
each  side  indented  by  an  independent  ramifying  sulcus,  which 
on  the  left  has  the  form  of  a  double  joined  Y,  and  on  ^he  right 
approaches  the  form  of  H.  Excepting  the  anterior  and  pos- 
terior, the  gyrus  has  one  superficial  connection  on  the  left 
(with  the  anterior  portion  of  the  second  temporal)  and  two  on 


30  AN  ESKIMO  BRAIN 

the  right  side  (with  the  anterior  part  of  the  second  temporal  and 
with  the  fusiform  lobule). 

The  fusiform  gyrus,  well  defined  on  both  sides,  is  throughout 
more  voluminous  on  the  right.  The  left  gyrus  shows,  near  its 
posterior  third,  a  shallow  interruption.  The  borders  of  both 
convolutions  are  indented  by  a  number  of  more  or  less  pro- 
nounced incisures.  The  gyri  show  numerous  submerged  con- 
nections with  the  third  temporal  and  the  lingual  convolutions. 

The  lingual  gyrus,  well  defined,  connects  on  both  sides, 
anteriorly,  superficially,  and  freely,  with  the  gyrus  hippocampi  ; 
posteriorly,  near  the  occipital  pole,  with  the  fusiform  lobules. 

The  gyrus  is  partly  divided  on  both  sides  into  halves  by  a 
branch  from  the  collateral  fissure.  The  anterior  portions  are  some- 
what tongue-  or  pear-shaped,  the  tapering  ends  connecting  with 
the  hippocampal  gyri,  and  each  is  indented  by  a  quite  prominent 
sagittal  sulcus.  The  posterior  extremity  of  this  sulcus,  on  the 
right,  connects  with  a  branch  from  the  collateral.  The  posterior 
half  on  the  left  is  nearly  straight  and  more  slender  than  the  an- 
terior one  ;  that  on  the  right  forms  a  marked  loop.  The  surface 
of  the  posterior  portions,  also,  is  indented  on  each  side  by  a  small, 
mainly  sagittal  depression. 

THE    LIMBIC    LOBE 

This  lobe  differs  remarkably  on  the  two  sides.  It  is  much 
larger  over  almost  its  entire  extent  on  the  right  side,  as  will  be 
indicated  by  the  following  measures  (taken  between  the  sulcus  of 
the  callosum  and  the  external  boundary  of  the  gyrus) : 

Left  Right 

Antero-inferiorly,  below  the  rostrum  (above  Broca's 

carrefour  olfactif) 0.3  cm.  0.5  cm. 

Anteriorly  (horizontally) 0.5  cm.  1.0  cm. 

Superiorly,    beneath    the   first   frontal   or   marginal 

gyrus 0.85  cm.  1.5  cm. 

Superiorly,  below  the  paracentral  lobule 1.5  cm.  2.1  cm. 

Superiorly,  below  the  precuneus 2.0  cm.  2.6  cm. 

Posteriorly,  opposite  the  cuneus 1.6  cm.  1.4  cm. 


AN  ESKIMO   BRAIN 


31 


The  lobe  begins  on  both  sides  at  the  well-developed  olfactory 
lobule  or  space  of  Broca,  below  the  rostrum  of  the  callosum.  Its 
ascending  portion  and  a  part  of  its  horizontal  portion  are  entirely- 
smooth  on  the  left ;  on  the  right  side  the  external  boundary  of  these 
parts  shows  many  depressions,  and  the  horizontal  part  is  traversed 
by  the  previously  described  sagittally  running,  shallow  sulcus. 

All  the  parts  of  the  limbic  lobe  behind  the  line  which  bounds 
anteriorly  the  paracentral  lobule  are  much  more  developed  than 
the  parts  anterior  to  this  line.  On  the  left  this  posterior  portion 
of  the  lobe  is  traversed  by  a  number  of  transverse  sulci  and  has 
the  appearance  of  being  composed  of  four  or  five  loops  lying  in 
close  apposition.  On  the  right,  there  is  a  somewhat  similar  for- 
mation of  loops,  but  their  outline  is  more  angular.  Directly 
beneath  the  splenium  both  lobes  become  very  narrow  and  soon 
after  blend  with  the  hippocampal  convolutions. 

Deep  bundles  connect  the  limbic  lobe  on  each  side  with  the 
mesial  part  of  the  first  frontal  gyrus  and  the  parietal  lobule. 
The  connections  of  the  lobe  with  the  precuneus  are  on  the  left 
all  submerged,  though  not  deep,  while  on  the  right  side  besides 
these  deep  bundles  there  is  also,  posteriorly,  a  superficial  annectent 
gyrus  between  the  two  structures.  A  few  deep  fascicles  pass 
between  the  lobe  and  the  cuneus  and  lingual  gyrus. 

HIPPOCAMPAL    GYRUS 

This  gyrus  is  somewhat  larger  on  the  right  side.  It  is  almost 
isolated  externally  on  the  right,  only  a  small  annectent  gyrus 
passing  from  it,  between  the  fissura  rhinica  and  the  inferior 
temporal  sulcus,  to  join  the  fusiform  convolution.  On  the  left 
side  this  connection  is  broader.  The  surface  of  the  gyri  is 
smooth.  Both  gyri  connect  superficially  with  the  lingual  con- 
volutions.    The  uncus  is  well  marked  on  both  sides. 

The  parts  within  the  limbic  lobe  show  nothing  extraordinary. 
The  callosum  is  exceptionally  strong  and  very  nearly  equal  on 
the  two  sides.     Its  measurements  are  as  follows : 


32  AN  ESKIMO  BRAIN 

Diameter  antero-posterior  maximum 7-9  cm- 
Maximum  height  of  anterior  enlargement i-45  cm- 
Maximum  height  of  posterior  enlargement 1.5    cm. 

Maximum  height  between  the  enlargements 1.0    cm. 

Minimum  height  between  the  enlargements 0.75  cm. 

The  dentate  gyrus  is  well  differentiated  and  the  fimbria  well 
developed. 

Cerebellum,  Pons,  Medulla 

All  these  parts  appear  to  be  very  well  developed  ;  they  are 
symmetrical  and  present  no  gross  deviation  from  the  shape 
and  conformation  of  the  same  parts  as  generally  observed  in 
whites. 

Measurements  of  Cerebellum 

Height  maximum 5-7  cm. 

(in  fresh  brain 5.8  cm.) 

Diameter  antero-posterior  maximum  1 6.8  cm. 

(in  fresh  brain 7.0  cm.) 

Width  maximum  2 10.4  cm. 

(in  fresh  brain 10.6  cm.) 

Antero-posterior  length  of  worm 4.3  cm. 

Maximum  height  of  worm 4.0  cm. 

Maximum  depth  of  anterior  fossa 2.2  cm. 

Maximum  depth  of  posterior  incisure 1.3  cm. 

Depth  to  the  top  of  the  worm  (from  a  plane  corresponding  to 

the  highest  points  on  each  cerebellar  hemisphere). 1.3  cm. 

Measurements  of  the  Pons 

Width  maximum 3.5  cm. 

Height  (vertical)  from  fourth  ventricle 2.9  cm. 

Length  (antero-posterior) 2.5  cm. 

Measurements  of  the  Medulla 

Thickness  maximum  infero-superiorly 1.8  cm. 

Thickness  maximum  laterally 2.0  cm. 

1  About  1.0  cm.  from  the  median  line  on  each  side. 

9  At  about  the  junction  of  anterior  third  with  posterior  two  thirds. 


AN  ESKIMO  BRAIN 


THE    CEREBELLUM 


33 


The  great  horizontal  fissure  encircles  the  organ  completely. 
It  averages  1.6  cm.  in  depth.  On  its  bottom  many  slender  rods 
are  seen  to  pass  from  one  part  of  the  cerebellum  (superior)  to 
the  other  (inferior),  all  directed  obliquely  outward.  (There  are 
similar  rods  within  all  the  other  sulci.) 

All  the  usual  lobes  of  the  upper  surface  (as  well  as  all  the 
divisions  of  the  worm)  are  present  and  well  developed.  There 
are  two  lobules  situated  laterally  to  the  lingula  (which  faces  for- 
ward) ;  these  two  lobules  are  joined  2  cm.  outward  to  the  alae 
lobuli  centralis.  These  last  are  very  small  and  hidden.  The 
lingula,  with  the  wings  and  the  central  lobule,  gives  a  very  good 
appearance  of  a  moth,  with  wings  converging  upward. 

Central  lobe  small.  Folium  cacuminis  double ;  uvula  con- 
sists of  eight  segments  of  which  the  last  two  (in  pyramid)  are 
small. 

The  pyramid  is  breast-shaped,  with  the  apex  posteriorly  and 
a  deep  notch  anteriorly  ;  into  this  notch  are  received  the  last  two 
little  segments  of  the  uvula.  The  lateral  masses  are  anteriorly 
separated  and  form  two  distinct  parts,  applied  over  the  ex- 
tremity of  the  uvula.  The  parts  connect  anteriorly  by  deep 
annectent  fascicles  with  the  cerebellum.  Tuber  portions  small. 
None  of  the  lobes  and  parts  of  the  lower  surface  and  lower  worm 
present  anything  extraordinary. 

Summary  of  the  Main  Peculiarities  of  Kishu's  Brain 

As  a  whole,  this  Eskimo  brain  is  heavier  and  larger  than  the 
average  brain  of  white  men  of  similar  stature.  The  excess  of 
weight  over  the  averages  of  both  Broca's  and  Manouvrier's  speci- 
mens (averages  which  agree  well  with  those  obtained  by  Bischoff, 
Boyd,  Sims,  Huschke,  and  other  observers)  amounts  to  almost 
150  grammes. 

As  to  size,  the  average  antero-posterior  diameter  of  the  white 
male  brain  ranges,  according  to  Huschke,  between  16.0  and  17.0 


34  AN  ESKIMO  BRAIN 

cm.  (mean  16.5  cm.),  and  the  average  maximumlateral  diameter 
14.0  cm.  The  mean  of  these  measures,  which  largely  removes 
the  disturbing  element  of  the  shape  of  the  brain,  is  15.25.  The 
crude  measurements  of  Kishu's  brain  amount,  for  the  length,  to 
18.0  cm.  for  the  left  and  17.9  cm.  for  the  right  hemisphere,  and 
13.6  cm.  for  the  maximum  breadth  of  the  cerebrum.  These 
figures  give  us  the  mean  of  16.5,  which  is  to  that  in  whites  as 
108.2  to  100. 

The  different  parts  of  the  brain  do  not  show  the  same  relative 
weight  proportions  as  they  do  in  the  average  white  brain,  and 
the  same  is  true  of  the  relative  size  of  the  principal  parts  of  the 
cerebrum.  The  cerebellum,  and  particularly  the  pons  with  the 
bulb,  is  relatively  somewhat  heavier  in  Kishu  than  in  whites  ; 
while  as  to  the  main  cerebral  parts  the  most  remarkable  feature 
is  the  relative  smallness  of  the  parietal  portion  (see  additional 
measurements). 

In  its  external  conformation  this  Eskimo  cerebrum  rather  ex- 
ceeds that  of  an  average  white  male  in  the  number,  extent,  and 
depth  of  the  sulci,  and  in  the  complexity  of  the  gyrations. 

Both  hemispheres,  and  especially  the  right  one,  show  a  gen- 
erally marked  tendency  to  vertical  gyration.  The  left  side  shows 
one,  the  right  two,  large,  anomalous,  composite,  vertical  furrows. 
The  gyration  of  the  left  hemisphere  is  in  general  somewhat  more 
complex  than  that  of  the  right  one. 

The  pars  triangularis  of  the  inferior  frontal  convolution,  the 
temporal  lobe,  inferior  parietal  gyrus,  and  limbic  lobe  are  all 
larger  on  the  right  than  on  the  left ;  on  the  other  hand,  the 
mesial  part  of  the  superior  frontal  gyrus,  the  middle  frontal  gyrus, 
the  paracentral  lobule,  the  precuneus,  and  the  mass  of  the  occipi- 
tal lobe,  are  larger  on  the  left  than  on  the  right  side. 

There  is  a  great  length  of  the  postcentral  sulci,  particularly  of 
that  on  the  left.  The  left  Sylvian  (main  limb)  is  longer,  the  left 
central  fissure  is  situated  (in  a  horizontal  direction)  slightly  more 
posteriorly  and  is  slightly  more  vertical  than  the  right.     There  is 


AN   ESKIMO  BRAIN 


35 


a  bilateral,  longitudinal  division  of  the  mesial  part  of  the  supe- 
rior frontal  gyrus  and  a  tendency  on  the  right  to  a  similar  division 
of  the  limbic  lobe  ;  and  on  each  side  there  is  a  pronounced  medio- 
temporal  sulcus,  dividing  sagittally  the  posterior  part  of  the  mid- 
dle temporal  convolution. 

Besides  those  enumerated,  there  are  many  other  interesting 
minor  features  of  the  brain  which  need  not  be  repeated. 

Comparative  Notes 

The  collection  in  the  Medical  Department  of  Columbia  Uni- 
versity includes,  besides  that  of  Kishu,  the  brains  of  three  other 
Eskimo  of  the  same  party  and  originally  from  the  same  locality 
(Smith  sound).  One  of  these  specimens  is  from  Nooktah,  a  man 
older  than  Kishu  ;  another  from  Atana,  a  woman  of  about  the 
same  or  a  little  more  advanced  age  than  Kishu  ;  and  the  third 
from  Avia,  a  girl  of  ten  to  twelve  years  of  age.  A  detailed  report 
on  these  three  brains  is  being  prepared,  as  hitherto  mentioned, 
by  Mr  E.  A.  Spitzka ;  my  independent  work  on  the  same  extends 
over  those  points  only  which  are  of  particular  interest  in  connec- 
tion with  the  specimen  here  described,  including  the  more  im- 
portant measurements. 

The  general  gyration  in  these  additional  Eskimo  brains,  com- 
pared with  that  in  average  adult  whites,  is  very  good,  particu- 
larly over  the  frontal  lobes,  in  Nooktah,  good  in  Atana,  rather 
simple  in  Avia.  In  all  the  external  conformation  is  more  com- 
plex on  the  left  hemisphere.  The  frontal  gyration  in  Nooktah  is 
not  less  complex  than  that  in  Kishu,  but  the  whole  brain  of  the 
latter  is  more  developed  and  richer. 

The  insulae  are  both  quite  exposed  anteriorly  in  Atana, 
less  so  in  Avia,  and  covered,  or  very  nearly  so,  in  Nooktah  as 
well  as  in  Kishu. 

The  ascending  frontal  gyri  are  both  very  strong  in  Atana,  the 
ascending  parietal  gyri  on  both  sides  and  the  ascending  frontal  on 
the  right  in  Avia. 


36  AN  ESKIMO  BRAIN 

The  anterior  and  posterior  portions  of  the  presylvian  are  sepa- 
rate in  all  three  brains,  as  in  that  of  Kishu. 

The  central  fissure,  which  in  Kishu  commenced  in  the  Syl- 
vian, has  a  similar  origin  on  the  right  side  in  Avia  ;  in  all  other 
instances  it  reaches  near  to  the  Sylvian.  The  superior  termina- 
tion of  the  fissure  reaches  the  superior  border  in  Nooktah  and  on 
the  right  in  Atana,  and  passes  slightly  to  moderately  over  it  on 
the  left  in  Atana  and  on  both  sides  in  Avia.  In  the  girl  the 
course  of  the  fissure  is  remarkably  vertical. 

A  longitudinal  division  of  the  mesial  part  of  the  superior 
frontal  gyrus,  found  in  Kishu,  is  also  present  complete  on  left, 
interrupted  on  right,  in  Nooktah  ;  slightly  incomplete  on  left, 
small  traces  on  right,  in  Atana ;  and  on  the  right  in  Avia. 

The  limbic  lobe  shows  traces  of  longitudinal  division,  as  on 
the  right  in  Kishu,  on  the  right  in  Nooktah,  and  on  the  left  in 
Avia.  The  lobe  that  shows  the  traces  of  division  is  in  both 
cases,  so  far  as  these  traces  extend,  higher  than  that  of  the  op- 
posite side,  as  was  also  the  case  in  Kishu. 

A  furrow  somewhat  similar  to  the  pre-precentral  vertical 
furrow  in  Kishu  is  seen  on  the  right  in  Nooktah,  while  sinu- 
osities, somewhat  similar  to  the  right  vertical  post-postcentral 
one  in  Kishu,  occur  on  the  left  in  Atana  and  on  the  right  in 
Avia. 

The  postcentral  sulcus  is  single  in  all  cases,  except  on  the 
left  in  Avia,  where  it  exists  in  two  portions. 

The  temporal  lobe  is  slightly  higher  on  the  left  side  in  Nook- 
tah and  Avia  (see  the  measurements).  The  first  temporal  gyrus 
is  in  all  cases  moderately  to  well  developed.  The  medio-tem- 
poral  sulcus,  though  present  in  segments  in  Nooktah  and  Atana, 
is  by  no  means  as  clearly  distinguishable  as  in  Kishu. 

Broca's  cap,  or  that  part  of  the  inferior  frontal  convolution  sit- 
uated between  the  two  portions  of  the  presylvian,  is,  contrary  to 
what  was  the  case  in  Kishu,  in  all  these  brains  better  developed 
on  the  left  side. 


AN  ESKIMO   BRAIN 


37 


The  extremities  of  the  occipital  lobes  are  in  all  three  brains 
of  about  equal  size  and  not  disproportionate  as  in  Kishu. 

Additional  and  Comparative  Measurements 

The  subject  of  brain  measurements  is  still  in  its  infancy. 
Although  many  brains  have  been  measured,  particularly  since 
Huschke  and  Broca,  there  is  yet  no  standard  system  of  encepha- 
lometry  comparable  with  that  of  the  measuring  of  the  head 
or  cranium.  Every  author  of  importance  has  thus  far  chosen  his 
own  points  from  which  to  measure,  and  there  is  no  regulation  of 
either  the  methods  or  instruments.  There  is  no  more  important 
part  of  the  body  and  at  the  same  time  no  part  with  which  more 
care  and  accuracy  are  required  in  measuring,  than  the  brain,  and 
these  two  conditions  ought  to  prompt  an  early  and  thorough 
systematization  of  procedure.  As  it  is,  the  brain  measurements 
of  one  author  can  scarcely  be  compared  or  joined  with  those  of 
any  other. 

The  most  disturbing  factors  in  measuring  the  brain  are,  first, 
its  softness  and  the  consequent  yielding  and  deformation  of  the 
organ  when  removed  from  the  cranial  cavity  ;  this  difficulty  can 
now  be  effectually  counteracted  by  a  formaline-alcohol  or  forma- 
line hardening  of  the  organ  before  the  opening  of  the  skull. 

The  second  important  factor,  which  thus  far  has  not  received 
sufficient  attention,  is  the  different  shape  of  the  brain  in  different 
individuals  and  especially  in  different  races.  No  one  would  think 
of  comparing,  or  uniting  in  a  series,  the  dimensions  of  a  dolicho- 
cephalic with  those  of  a  brachycephalic  skull,  and  similar  distinc- 
tions should  be  established  in  brain  measurements. 

The  choice  of  instruments  is  very  important.  Even  if  the 
tape  only  be  used,  considerable  differences  in  the  measurements 
are  obtained  according  to  the  width  of  the  same. 

Some,  and  perhaps  many,  of  the  measurements  of  the  brain 
carry  valuable  indications  which  we  today  do  not  appreciate. 
The  knowledge  of  the  organ  will  certainly  progress,  and  meas- 


38  AN  ESKIMO  BRAIN 

urements  taken  with  care,  even  if  not  essential  now,  may  in  the 
future  be  found  of  value. 

A  more  detailed  discussion  here  of  these  important  matters 
would  be  somewhat  irrelevant  to  the  subject  of  this  paper.  The 
above  remarks  are  thought  to  be  a  proper  introduction  to  the 
following  figures  and  comparisons. 

The  measurements  of  Kishu's  brain,  which  was  carefully  pre- 
served, between  cotton,  in  a  mixture  of  formaline  and  alcohol, 
are,  as  I  have  certified  on  the  skull,  almost  absolutely  correct. 
The  brains  of  Nooktah,  Atana,  and  Avia  were  preserved  in  a 
weak  solution  of  formaline.  Nooktah's  brain  is  fairly  well  pre- 
served and  its  measurements  are  apparently  quite  correct ;  the 
brains  of  Atana  and  Avia,  however,  have  suffered  a  rather  con- 
siderable change  in  form,  and  the  absolute  measurements  of  these 
specimens  have  but  little  meaning.  The  relative  proportions  of 
the  various  parts  of  the  cerebrum  were  undoubtedly  much  less 
affected  than  the  absolute  measurements  and  are  probably  still  fit 
for  consideration. 

The  surface  measurements  were  taken  by  a  tape  0.8  cm. 
broad,  while  the  diameters  were  obtained  on  a  graduated  plane 
(Mathieu's)  and  by  the  accurate  sliding  compass  used  in  osteom- 
etry. Three  repeated  measurings  gave  fairly  even,  though  in  but 
very  few  instances  exactly  the  same,  results. 

The  points  from  which  the  various  dimensions  were  taken  and 
the  methods  will  be  explained  with  each  measurement. 

Measurements 
approximate   length  of  the  lines  of  norma    anterior,    kishu  : 

Left  Right 

Antero-lateral  lines 11.5  cm.  10.3  cm. 

Anterior  lines  1 8.3  cm. 

Postero-lateral  lines 8.2  cm.  7.8  cm. 

Posterior  lines  2 5.9  cm. 

1  Taken  between  two  cardboards  applied  to  the  antero-lateral  planes  of  the  brain, 
the  line  measured  touching  the  anterior  surface  of  the  frontal  lobes. 

2  Obtained  in  a  way  similar  to  that  of  the  anterior  lines. 


AN  ESKIMO  BRAIN  39 

MAXIMUM    LENGTH    OF    THE    HEMISPHERES 

Left  Right 

Kishu 18.0  cm.  17.9  cm. 

Nooktah 16.8  cm.  17.0  cm. 

Atana (17.1cm.)  (17.1cm.) 

Avia (15.3  cm.)  (15.3  cm.) 

In  one  of  the  males  the  length  of  the  left  exceeds  slightly 
that  of  the  right  hemisphere,  while  in  the  other  male  the  condition 
is  reverse;  in  the  two  females  the  length  of  both  hemispheres  is 
equal. 

In  whites  the  left  hemisphere  is  almost  generally  slightly 
longer  (Eberstaller,1  Cunningham  2). 

MAXIMUM     WIDTH     OF    THE    CEREBRUM  ;     CEREBRAL    INDEX,     COMPARED 

to  cephalic  (on  the  living). 

(Breadth  X  ioo\  /  Breadth  of  Head  X  ioo\ 
Length         '  V         Length  of  Head        I 

Kishu 13.6  cm.  75.8  76.26 

Nooktah....      13.1cm.  77.5  81.4 

Atana (12.3  cm.)  (7 1.9)  80.6 

Avia (n. 6  cm.)  (75-8)  72.9 

It  can  be  seen  that  while  the  brains  of  Kishu  and  Nooktah 

have  kept  nearly  the  same  relative  proportions  as  they  must  have 

had  in  life,  that  of  Atana  became  relatively  longer  and  narrower 

and  that  of  Avia  shorter. 

ARC    MEASURES   ALONG    THE    SUPERIOR  BORDER  S 
a.  Anterior  Point  (Cunningham)  to  Central  Fissure. 
Left  Right 

Kishu..    17.0  cm.  or  63.0$,    17.7  cm.  or  65.1$  of  the  total  mesial  length. 
Nooktah   16.7  cm.  or  66.5  <f0,     16.7  cm.  or  64.5  <f0. 
Atana. .  (15.3  cm.  or  59.8  #),  (15.0  cm.  or  60.5  <£). 
Avia. .    (15.5  cm.  or  64.6$),  (15.0  cm.  or  62.5  f0). 

'Eberstaller,  Das  Stirnhirn,  Wien  and  Leipzig,  1890. 

'Cunningham,  D.  J.,  "  Contrib.  to  the  Surface  Anatomy  of  the  Cerebral  Hem- 
ispheres." Roy.  Irish  Acad.,  Cunningham  Mem.,  VII,  1892.  All  the  following 
references  to  Cunningham  relate  to  this  work. 

8  Eberstaller  measured  from  the  anterior  perforated  space  to  the  occipital  pole. 
Cunningham,  whom  I  follow,  takes  the  same  measures  "from  a  point  on  the  upper 
or  mesial  border  which  corresponds  to  the  level  of  the  outer  part  of  the  superciliary 


40  AN  ESKIMO  BRAIN 

This  relative  length  of  the  precentral  part  to  the  total  mesial 
arc,  this  latter  being  taken  as  ioo,  is  termed  by  Cunningham  the 
frontal  or  fronto-Rolandic  index,  and  is  in  whites,  according  to 
the  same  author  (pp.  55,  175),  as  follows  : 

In  12    5^  to  d\  mos.  embryos 52.7 

In  24  full-term  foetuses 53.5 

In  82  adults 53-3 

In  apes  and  monkeys  from  55.9 

in  chimpanzee  to  45.4 

in  mangaby. 

b.    Central  to  Parieto- Occipital  Fissure 
Left  Right 

Kishu 4.3  cm.  or  15.9  <f0,     4.3  cm.  or  15.8  <f0  of  the  mesial  arc. 

Nooktah. ...      3.9  cm.  or  15.5  $,     5.0  cm.  or  19.3  %  of  the  mesial  arc. 

Atana (5.8  cm.  or  22.7  f0),  (5.2  cm.  or  21.0  <f0)  of  the  mesial  arc. 

Avia (5.1  cm.  or  21.2  <f0),  (5.3  cm.  or  22.1  f0)  of  the  mesial  arc. 

Cunningham,  who  terms  the  proportion  of  the  central  parieto- 
occipital fissure  segment  to  the  whole  mesial  arc  (this  being  taken 
as  100,  the  parietal  index),  obtained  the  following  in  whites  (p.  55): 

Parietal  Index 

In  12  5 1  to  d\  mos.  embryos 28.5 

In  24  full-term  foetuses 25.7 

In  82  adults 25.5 

In    4  orangs 21.3 

Further,  in    4  chimpanzees 19.9 

In    5  cynocephali 22.6 

In    5  macaques 19.0 

In    7  cebi 20.6. 

margin  of  the  frontal  lobe.  This  border  is  very  far  from  being  horizontal.  Its  outer 
part  is  on  a  much  higher  level  than  the  inner  part.  As  it  is  traced  inwards  it  is  seen  to 
take  a  sudden  curve  downwards  towards  the  cribriform  plate  of  the  ethmoid  bone, 
where  it  merges  with  the  mesial  border.  A  line  drawn  horizontally  inwards  from  the 
high  outer  part  of  the  superciliary  border  of  the  frontal  lobe  cuts  the  mesial  border  of 
the  cerebrum  at  the  point  which  I  arbitrarily  selected  as  the  anterior  end  of  the  cere- 
brum. It  lies,  as  a  rule,  just  below  the  most  projecting  part.  Behind  I  took  the  most 
prominent  part  of  the  occipital  pole."  "  The  first  of  these  points  maybe  distinguished 
as  the  frontal  point,  and  the  latter  as  the  occipital  point.  Further,  the  distance  between 
these  two  points  measured  along  the  upper  border  of  the  hemisphere  may  be  termed 
the  mesial  length."     (Loc.  cit.,  pp.  xi,  xii.) 

Cunningham's  anterior  point  has  no  advantage  over  that  of  Eberstaller,  and  I  em- 
ploy it  only  to  enable  comparison  of  my  own  with  Cunningham's  indices. 


AN   ESKIMO   BRAIN  4 1 

c.    Parietooccipital  Fissure  to  most  Prominent  Point  on  the  Occipital  Pole 
Left  Right 

Kishu 5.7  cm.  or  21.1  <fc,     5.2  cm.  or  19. 1  $  of  the  mesial  arc. 

Nooktah .  . .  .4.5  cm.  or  17.9  <fc,     4.2  cm.  or  16.2  f0  of  the  mesial  arc. 

Atana (4.5  cm.  or  17.6  f0),  (4.6  cm.  or  18.5  <f)  of  the  mesial  arc. 

Avia (3.4  cm.  or  14.2  <fi),  (3.7  cm.  or  15.4  <?0)  of  the  mesial  arc. 

Cunningham  terms  the  relative  distance  of  the  parieto-occipital 
fissure  from  the  most  prominent  point  in  the  occipital  pole  the 
occipital  index,  and  obtained  for  whites  (pp.  55,  56): 

In  12  5^-6^-  mos.  embryos 18.8 

In  24  full-term  foetuses 20.8 

In  82  adults 21.2  ;  also,  in 

4  orangs 23.2 

4  chimpanzees 24.2 

5  cynocephali 29.7 

5  macaques 31.0 

7  cebi 33.0. 

Among  adult  whites,  in  45  men  the  occipital  index  was  20.8  ; 
in  35  women  the  occipital  index  was  21.7. 
The  total  mesial  arc  (from  the  anterior  point,  Cunningham, 
to  the  most  prominent  point  on  occipital  pole)  was : 

Left  Right 

Kishu 27.0  27.2 

Nooktah 25.1  25.9 

Atana (25.6)  (24.8) 

Avia (24.0)  (24.0). 

The  above  indices  show  in  the  Eskimo  some  remarkable  features 
which  are  undoubtedly  more  than  individual  variations.  There  are 
in  all  the  Eskimo,  but  especially  in  the  men,  relatively  high  frontal 
and  low  parietal  indices.  The  parietal  indices  in  the  two  females 
and  the  occipital  indices  in  the  two  males  and  the  adult  female, 
though  also  lower,  approach  more  those  in  whites.  There  is  in 
the  four  Eskimo,  according  to  these  surface  measurements,  rela- 
tively a  more  extended  superior  frontal  and  a  more  restricted 
superior  parietal  area  than  in  the  average  whites.1 

1  Compare  in  this  connection,  and  with  the  horizontal  dimensions  that  follow,  the 
seemingly  conflicting  measures  of  Fere,  Passet,  and  Giacomini,  referred  to  by  Dejerine, 


42  AN  ESKIMO  BRAIN 

There  is  another  and  somewhat  more  accurate  way  in  which 
the  dimensions  of  the  main  parts  of  the  cerebrum  may  be  deter- 
mined. If  the  hardened  hemisphere  is  placed  on  the  graduated 
board  in  such  a  way  that  the  most  prominent  frontal  and  occipital 
points  are  on  a  line  which  runs  lengthwise  along  the  middle  of 
the  board,  we  can  then  secure,  by  means  of  two  vertical  planes 
and  a  rod-measure  or  an  ordinary  compass,  any  desirable  horizon- 
tal distance  from  the  cerebral  extremities.  Such  distances,  com- 
pared with  the  total  horizontal  length  of  the  hemisphere,  give 
indices  which  are  somewhat  more  accurate  and  perhaps  not  inferior 
in  value  to  those  obtainable  by  surface  measuring.  Following 
this  procedure  on  the  Eskimo  brains,  I  have  obtained  the  following 
figures  and  proportions: 

a.   Horizontal  Length,  Frontal  Pole  to  Superior  Extremity  of  Central  Fissure 
Left  Right 

Kishu....    10.9  cm.  or  60.6  $,     10.8  cm.  or  60.4  $ 

of  the  length  of  the  hemisphere. 
Nooktah..    10.9  cm.  or  64.9  f0,     10.7  cm.  or  62.9$ 

of  the  length  of  the  hemisphere. 
Atana (9.6  cm.  or  56.1  </0),  (10.0  cm.  or  58.5  f0) 

of  the  length  of  the  hemisphere. 
Avia (9.8  cm.  or  64.1  f0),    (9.3  cm.  or  60.8  %) 

of  the  length  of  the  hemisphere. 

b.  Horizontal  Distance,  Superior  End  of  Central  to  Parieto-occipital  Fissure  1 
Left  Right 

Kishu....      4.1  cm.  or  22.8  <f0,    4.0  cm.  or  22.3  <f0 

of  the  length  of  the  hemisphere. 
Nooktah..      2.3  cm.  or  13.7  </0,    3.5  cm.  or  20  6  f0 
of  the  length  of  the  hemisphere. 

Anat.  d.  Centres  Nerveux,  Paris,  1895,  p.  249.  The  coincidence  of  the  relatively 
somewhat  small  occipital  with  relatively  small  parietal  lobes  is  quite  curious.  Gratiolet 
(quoted  by  Cunningham,  p.  59)  states  that  in  man  the  occipital  lobe  is  extremely  re- 
duced ;  and  formulates  the  law  that  "the  more  highly  organized  a  member  of  the 
group  is,  the  smaller  is  the  relative  size  of  the  occipital  lobe."  Quite  as  striking,  how- 
ever, is  the  small  relative  size  of  the  parietal  lobe  in  the  ape. 

1  The  measurements  are  taken  between  the  points  of  intersection  by  the  fissures  of 
the  superior  border  of  the  hemisphere.  Where  the  parieto-occipital  fissure  bifurcated 
before  reaching  the  superior  border  (left  in  Atana,  right  in  Avia),  the  measurement 
was  taken  to  a  prolongation  of  the  main  limb  of  the  fissure.  Same  with  surface 
measurements. 


AN  ESKIMO  BRAIN 


43 


Left  Right 

Atana. .  (5.1  cm.  or  29.8  f0),  (4.6  cm.  or  26.9  <f) 

of  the  length  of  the  hemisphere. 
Avia. . . .  (4.0  cm.  or  26.1  fo),  (4.4  cm.  or  28.8  </0) 

of  the  length  of  the  hemisphere. 

c.  Horizontal  Distance,  Parielo-occipital  Fissure  to  Occipital  Pole 
Left  Right 

Kishu. ...  3.0  cm.  or  16.7  <f0,     3. 1  cm.  or  1 7.3  <f0 

of  the  length  of  the  hemisphere. 
Nooktah.  3.6  cm.  or  21.4$,     2.8cm.  or  16.5  $ 

of  the  length  of  the  hemisphere. 
Atana. .  .  (2.4  cm.  or  14.0  $),  (2.5  cm.  or  14.6  <f) 

of  the  length  of  the  hemisphere. 
Avia....  (1.5  cm.  or  9.8$),  (1. 6cm.  or  10.5  $) 

of  the  length  of  the  hemisphere. 

These  measurements  show  almost  generally  a  higher  relative 
proportion  of  the  region  between  the  central  and  parieto-occipital 
fissures  than  was  the  case  with  the  surface  measurements,  which 
indicates  that  the  region  is  relatively  more  flat  than  the  others. 

Two  more  notable  facts  shown  by  both  the  arc  and  the  hori- 
zontal measurements  are  a  very  small  parietal  and  a  large  occipi- 
tal portion  on  the  left  in  Nooktah  and  the  small  occipital  portions 
in  Avia. 

A  more  detailed  study  of  the  figures  shows  that,  so  far  as 
their  size  is  concerned,  the  main  portions  of  the  cerebrum  tend  to 
compensate  each  other. 

DISTANCE  OF  THE   LOWER   EXTREMITY   OF   THE   CENTRAL   FISSURE   FROM 

THE    FRONTAL    POLE 

Cunningham  measured  this  distance  over  the  surface  of  the 
frontal  lobe,  comparing  the  dimension  thus  obtained  with  the  entire 
arc  running  in  the  same  line  from  the  mesial  border  of  the  ante- 
rior to  that  of  the  posterior  extremity  of  the  hemisphere.  I  have 
followed  the  same  method,  but  have  supplemented  it  with  the 
horizontal  distance,  as  with  the  preceding  measurements.  The 
results  are  as  follows  : 


44  AN  ESKIMO  BRAIN 

Surface  Distance  of  the  Base  of  the   Central  Fissure  fro?n    the  Mesial  Border   of 

the  Anterior  Extremity 


a.  Arc  to  the  base 

of  central  fissure.       b.  Complete 

:  lateral  arc. 

Centesimal  relation 

of  a 

to  b. 

Left 

Right                      Left 

Right 

Left 

Right 

Kishu. . . 

10.8  cm. 

11. i  cm.       25.2  cm. 

24.5  cm. 

42.9 

45-3 

Nooktah. 

10.7  cm. 

10.5  cm.        23.3  cm. 

23.1  cm. 

45-9 

45-5 

Atana. . . 

.    (n. 2  cm. 

10.6  cm.)   (22.9  cm. 

23.1  cm.) 

(48.9 

45-9) 

.    (  8.0  cm. 

8.6  cm.)    (21.3  cm. 

21. 1   cm.) 

(37-6 

40.8) 

The  centesimal  relation  of  a  to  b  is  termed  by  Cunningham 
(p.  179)  the  lower  Rolandic  index  and  was: 

In  17  adult  whites,  males 43.7 

In  20  adult  whites,  females 43.0 

The  index  differed  but  little  in  children  and  human  embryos  ; 
in  apes  and  monkeys  it  ranged  (p.  175)  from  39.2  in  the  orang  and 
chimpanzee  to  43.8  in  cebus. 

The  horizontal  distance  of  the  base  of  the  central  fissure  from 
the  frontal  extremity,  and  its  centesimal  relations  to  the  length 
of  the  hemisphere,  are  as  follows : 

a.  Distance  to  base  of  central  fissure.  Centesimal  relation  of  a  to 

length  of  hemisphere 
Left  Right  Left  Right 

Kishu 7.3  cm.  6.5  cm.  40.6  36.3 

Nooktah 7.6  cm.  7.5  cm.  45.2  44.1 

Atana (8.3  cm.  7.8  cm.)  (48.5  45-3) 

Avia (5-4cm.  5.9  cm.)  (35.3  38.6). 

LENGTH    OF    THE    CENTRAL    FISSURE 

a.  Diameter,  from  lower  to  upper  extremity,  b.  Length  measured  by  a  thread  fol- 
taken  by  the  sliding  compass.  lowing  all  the  windings  of  the  fissure. 

Centesimal  relation  of  a  to  Centesimal  relation  of  b 

length  of  hemisphere.  to  mesial  length. 

I.  r.  I.  r.  I.  r.  I.  r. 

Kishu 9.0  8.6  50.0  48.0  11. 7  11. 5  43.0  42.3 

Nooktah....  8.0  8.4  47.6  49.4  10.7  11.0  42.6  42.5 

Atana (7.3  7.7)  (42.7  44.9)  (10.8  10.6)  (42.2  42.7) 

Avia (7.9  7.7)  (51.6  50.3)  (11.0  10.3)  (45.8  42.9) 


AN  ESKIMO  BRAIN  45 

Cunningham  (p.  191),  taking  the  length  of  the  fissure  accord- 
ing to  b  and  comparing  it  with  the  mesial  arc,  obtained  in  whites  : 

In  5!  to  b\  mos.  embryos 16.7 

In  full-term  foetuses 32.8 

In  4-  to  5-year-old  children 33.9 

In  16  adult  females 40. 1 

In  14  adult  males 38.6 

and  in  the  chimpanzee 5 1. 1 

orang 47.2 

hamadryas 41.1 

The  length  of  the  fissure,  as  seen  from  the  above,  is  relatively 
greater  in  the  Eskimo  than  in  the  whites  ;  there  is  no  decided 
sexual  difference. 

The  straight  length,  or  diameter,  of  the  fissure  can  serve,  in 
connection  with  the  horizontal  measures  (from  the  vertical  plane 
rising  from  the  anterior  extremity  of  the  hemisphere  to  the  two 
extremities  of  the  fissure),  in  determining  a  Rolandic  angle  (by 
projection). 

LENGTH    OF    THE    SYLVIAN 

Taking  this  length  with  a  compass,  from  the  exterior  point  of 
intersection  of  the  Sylvian  by  the  anterior  or  horizontal  portion 
of  the  presylvian,  to  the  angle  which  the  ascending  terminal 
branch  forms  with  the  main  limb  of  the  Sylvian,  Eberstaller 
(quoting  Cunningham)  found  it  in  whites  as  follows : 

Up  to  5.0  cm.,  left  in  22  <f0,  right  in  45  tf0  of  hemispheres. 

5.1-6.0  cm.,  left  in  42  f0,  right  in  44  <f0  of  hemispheres. 

6.1-7.0  cm.,  left  in  27  f0,  right  in  11  $  of  hemispheres. 

Over  7.0  cm.,  left  in    9  $,  right  in  0.6  <f0  of  hemispheres. 

These  figures  show  that  the  left  Sylvian  is  more  often  the 
longer.  Cunningham  (p.  122)  obtained  similar  results,  but  he 
measured  the  fissure  from  "  the  point  at  which  its  trunk  appears 
on  the  outer  surface  of  the  hemisphere."  As  this  point  is  almost 
generally  less  clearly  defined  than  that  employed  by  Eberstaller, 


46  AN  ESKIMO  BRAIN 

I    follow    the    latter    authority.      The    Sylvians    in    the    Eskimo 
measured  as  follows : 

Centesimal  relation  to  the  length  of  the 
hemisphere 

Left  Right  Left  Right 

Kishu 6.5  5.2  36.1  22.9 

Nooktah 6.2  4.8  36.9  28.2 

Atana (6.4  5.1)  (37.4  29.8) 

Avia (5.4  5-9)  (35-3  38.6) 

The  left  fissure  is,  in  three  of  the  Eskimo,  both  absolutely  and 
relatively,  decidedly  longer  than  the  right  one. 

Two  additional  useful  and  quite  easy  measures  are,  I  think, 
the  maximum  breadth  of  the  frontal  lobes,  measured  by  the 
sliding  compass,  with  the  branches  applied  over  the  most  promi- 
nent points  on  the  dorsum  of  the  orbital  parts  of  the  inferior 
frontal  gyri  ;  and  a  diameter  between  the  extremities  of  the  tem- 
poral and  occipital  lobes.  These  dimensions  in  the  Eskimo  are 
as  follows  : 

BREADTH  OF  THE  FRONTAL  LOBES 

Centesimal  proportion  to  maximum. 
Breadth  width  of  the  cerebrum 

Kishu n. 5  cm.  84.6 

Nooktah 10. o  cm.  76.3 

Atana (7.9  cm.)  64.2 

Avia (7.5  cm.)  64.7 

These  figures  demonstrate  well  the  superiority  of  the  frontal 
lobes  in  Kishu's  cerebrum,  and  the  inferiority  in  this  respect  to 
both  the  males  of  both  of  the  females. 

TEMPORO-OCCIPITAL    LOBES 


Left 

Kishu 14.2  cm. 

Nooktah 13.2  cm. 

Atana (13.1cm.) 

Avia (12.0  cm.) 


Centesimal  relation  to  the  length 
of  the  hemispheres 

Right 

Left 

Right 

14.3  cm. 

78.9 

79-9 

13.5  cm. 
(13.4  cm.) 
(11. 7  cm.) 

78.6 

(76.6) 
(78.4) 

79-4 
(78.4) 
(76.5) 

AN  ESKIMO  BRAIN  47 

In  this  particular  measurement  the  four  brains  show  remarkable 
similarity. 

PREVIOUS  RECORDS  ON  ESKIMO  BRAINS 

The  only  previous  records  concerning  Eskimo  brains  of  which 
I  could  learn  are  those  made  by  Chudzinski,  published  in  the 
Bulletin  de  la  Soci/te d 'Anthropologic  de  Paris,  1886. 

The  brains  described  by  this  author  were  those  of  Tobias 
Ignatius,  male,  23  years;  Paulus  Abraham,  male,  35  years;  and 
Ulrika  Henocq,  female,  24  years.  The  locality  from  which  these 
subjects  came  is  not  stated,  but  there  are  reasons  to  believe  that 
they  belonged  to  the  eastern  Greenland  Eskimo. 

The  three  brains  present  some  interesting  similarities,  but  also 
many  characteristics  different  from  those  of  any  of  the  specimens 
noted  in  this  paper.  In  order  to  facilitate  a  comparison  I  shall 
introduce  the  principal  part  of  Chudzinski's  report. 

The  brains  show  "  a  considerable  volume  of  the  cerebral  hemi- 
spheres "  ;  "  then  one  can  see  that  the  convolutions  which  con- 
stitute the  external  surface  of  the  hemispheres.are  large,  simple, 
and  very  poor  in  secondary  divisions,  and  that  the  sinuosities  are 
but  little  flexuous."  "  That  simplicity  is  especially  marked  over 
the  frontal  lobes " ;  "  the  same  lobes  are  at  the  same  time 
flattened  infero-superiorly." 

"  The  Sylvian  fissure  appears  to  be  shorter  than  ordinarily, 
nearly  horizontal,  and  of  very  simple  contours,"  except  in  the 
woman,  where  it  is  little  more  complex,  especially  on  the  right. 
"  Its  anterior  branch  is  generally  very  short  and  in  the  brain  of 
P.  A.  altogether  hidden  by  the  temporal  lobe." 

"  The  Rolandic  fissure  is  very  long."  "  It  is  flexuous,  espe- 
cially in  P.  A.     Ends  on  mesial  surface  "  (in  all  ?). 

"  Occipital  fissure  very  short  externally.  Calcarine  fissure  long 
and  flexuous,  especially  in  U.  H." 

"  The  frontal  lobe  is  relatively  short ;  the  other  lobes  are,  on 
the  contrary,  well  developed,  especially  the  parietal." 


48  AN  ESKIMO  BRAIN 

"  The  first  frontal  gyrus  is  very  large,  especially  in  Tobias,  but 
shows  only  a  few  incisures." 

"  The  development  of  the  second  convolution  is  enormous, 
especially  in  P.  A."  "  The  gyrus  is  very  simple  in  Tobias." 
"  Among  other  features,  there  is  a  double  anastomosis  with  the 
ascending  frontal." 

"  The  third  frontal  gyrus  is  very  little  developed  ;  it  is  short 
and  as  ramassie  sur  elle  mime"  "  In  Tobias  it  is  reduced  to  a 
small,  nearly  smooth  isle."     Better  developed  in  U.  H. 

"  Ascending  frontal  gyrus  very  large."  "  Ascending  parietal 
gyrus  very  flexuous  in  Paulus,  very  large  in  Tobias."  The  two 
gyri  (asc.  frontal  and  asc.  parietal)  are  slender  in  U.  H. 

"  The  parietal  convolutions  generally  simple  and  very  ex- 
tended," especially  the  second  inferior. 

"  Occipital  lobe  generally  simple,  especially  in  Tobias." 

Temporal  lobe:  "  Extreme  slenderness  of  first  convolution  "  ; 
"  uncommon  size  of  second  convolution." 

Internal  (mesial)  surface  :  "  Enormous  development  in  breadth 
of  the  mesial  part  of  the  first  frontal  convolution,  especially  in 
Tobias;  a  division  of  that  convolution  into  two  secondary  gyri 
by  an  uninterrupted  sulcus  on  the  left  hemisphere  in  Paulus." 
The  secondary  sulcus  seems  to  be  continuous  with  the  subfrontal 
fissure.  Similar  sulcus  on  right  in  Paulus,  but  in  several  places 
interrupted  by  annectent  gyri. 

The  convolution  of  the  corpus  callosum  is  generally  very  ex- 
tended ;  but  its  breadth  is  very  remarkable  in  Tobias,  in  its  pos- 
terior part,  and  anteriorly  in  Ulrika,  in  whom  it  seems  to  divide 
itself  along  its  middle  into  two  secondary  gyri." 

The  ovalaire  lobule  is  enormous  in  Ulrika  ;  on  the  other  hand, 
the  cuneiform  is  small,  and  in  Ulrika  it  is  reduced  to  a  " pli  de 
passage"  hidden,  in  large  part,  in  the  calcarine  and  occipital 
fissures. 

The  similarities  in  the  brains  reported  upon  by  Chudzinski 
and  the  one  described  here  consist  of  the  large  volume  of  the 


AN  ESKIMO  BRAIN 


49 


cerebral  hemispheres;  long  central  fissures;  sagittal  division  of 
the  mesial  parts  of  the  superior  frontal  gyri ;  the  large  size  of  the 
limbic  lobe  in  Tobias,  and  the  large  size  of  the  lobe  with  a  ten- 
dency toward  a  longitudinal  division  in  Ulrika. 

The  dissimilarities  are  :  the  poor  differentiation  in  Chudzinski's 
specimens  of  the  convolutions  and  the  simple  character  of  the  sulci, 
especially  over  the  frontal  lobes;  a  defective  development  of  the 
inferior  frontal  convolution  (particularly  in  Tobias);  very  large 
ascending  frontal  and  ascending  parietal  convolutions  ;  simplicity 
of  parietal  convolutions ;  great  slenderness  of  the  superior  temporal 
gyri ;  and  very  small  cuneus. 

The  causes  of  the  many  dissimilarities  are  not  clear.  The 
morphological  inferiority  of  the  two  male  brains  described  by 
Chudzinski,  and,  on  the  other  hand,  the  marked  superiority  of 
Kishu's  and  even  of  Nooktah's  brain,  may  be  to  some  extent 
individual  conditions  and  represent  more  the  extremes  than  the 
average  of  Eskimo  brains.  At  the  same  time  it  is  possible  that 
Paulus  Abraham  and  Tobias  Ignatius  belonged  to  some  family 
of  the  great  Eskimo  tribe  intellectually  less  developed  than  the 
Smith  Sound  group  to  which  Kishu  and  Nooktah  belonged.  The 
Smith  Sound  party  which  Lieutenant  Peary  brought  to  New 
York  were  by  no  means  dull  or  incapable  people.  This  is  espe- 
cially well  demonstrated  in  Menee,  the  son  of  Kishu,  who  has  not 
only  shown  a  remarkable  facility  for  adjusting  himself  in  every 
way  to  civilized  life,  but  has  made  very  good  progress  in  the 
public  school. 

The  marked  differences  of  the  specimens  described  by  Chud- 
zinski and  in  this  paper  from  those  of  the  whites,  as  well  as 
among  themselves,  makes  a  future  acquisition  of  Eskimo  brains 
very  desirable. 


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